CHAPTER 1

Grandmother Died

Elizebeth Friedman, U.S. Coast Guard

Cryptanalyst-in-Charge, and a junior cryptanalyst,

Robert Gordon, puzzling out a problem together, 1940.

(George C. Marshall Research Foundation)

Lights out ’cause I can see in the dark . . .

—FUGAZI

The Second World War did not begin with a gunshot or a bomb. It began with a feat of deception involving elements long familiar to Elizebeth Friedman—a code phrase, a radio station, and a murder. The men responsible were Nazis, and they belonged to the same part of the Nazi state that would soon attract Elizebeth’s deep attention.

At 4 P.M. on August 31, 1939, in a hotel room in a small Polish town four miles from the German border, a Nazi officer named Alfred Naujocks dialed a number in Berlin. Someone in Berlin picked up. A high-pitched voice said, “Grossmutter gestorben.” “Grandmother died.” Naujocks hung up. He went to gather his team, the six operatives he had brought across the border. “Grandmother died” was the signal to execute a preplanned mission at 8 P.M.

The mission was to provide Germany with an excuse to start a war. Hitler had already decided to attack Poland, to seize his neighbor to the east, but he did not want to appear as the aggressor, so a pretext was needed, a simulated attack on German forces that would allow Hitler to claim he was acting in self-defense and create confusion about where the truth really lay.

This is where Naujocks and his colleagues entered the picture. They would invent the proof of Polish aggression.

They belonged to the SS, the chief instrument of Nazi terror. They were the men in black, the storm troopers, numbering 250,000 by 1939. They wore the death’s-head symbol on their uniforms, the skull and crossbones. As individuals they were like any other large group of humans, containing multitudes: opportunists, idealists, fanatics, scholars, mediocrities, petty crooks. But as a collective they became “the guillotine used by a gang of psychopaths obsessed with racial purity,” in the words of the historian Heinz Höhne. It was SS men who built the concentration camps and managed the ghettoes and trains that herded and transported Jews and other minorities into the camps to be enslaved, tortured, and killed. They were the guards at Dachau and Auschwitz, the murderers of millions. They were the mobile killing units, the Einsatzgruppen, that swept in behind the advancing German military, shooting resisters and Jews. They were the Gestapo, the ruthless Nazi police. They were the Nazi intelligence men, the ones who spied on their fellow Germans to keep them in line, and they were the spies who worked undercover in other nations, extending the reach of the regime until it encircled the world. And they were not meant to be confronted or understood. One SS leader bragged that the organization was “enveloped in the mysterious aura of the political detective story.” Elizebeth would spend much of the war trying to penetrate this veil.

After the SS men in Poland received the code phrase over the phone on August 31, they waited until just before dusk, then drove two cars through the pine forest toward their objective, a Nazi radio station that transmitted propaganda broadcasts. The plan was to pose as Polish insurgents, take over the station, and broadcast a message denouncing the Führer. They stopped near the station and met a Gestapo captain to pick up what they had been calling “Canned Goods”: the unconscious body of an SS prisoner, a forty-three-year-old Catholic farmer named Franz Honiok. He had been shot, sedated, and dressed in a Polish uniform. His face was smeared with blood. Naujocks carried him to the steps of the station and left him there slipping away from his fatal gunshot wounds, then stormed into the broadcast area with his team, aiming a revolver at the staff: “Hands up!” One of the SS men spoke Polish. He grabbed the emergency microphone used for storm warnings. “Attention, this is Gliwice,” he shouted in Polish, pretending to be an insurgent. “The radio station is in Polish hands.” He called for an uprising. The men fired bullets into the ceiling to simulate an armed struggle.

Thousands of radio listeners heard the gunfire and the burst of Polish. Two hours later stations in Berlin were spreading news of the “Polish attack.” The BBC in London reported that “Poles forced their way into the studio.” And while diplomats around the world tried to get a fix on the truth, the Nazis were massing at the border. At dawn on September 1, 1939, the morning after the incident in Gliwice, the Wehrmacht sliced into Poland, forty-two divisions all at once, with one and a half million men. It was the middle of the night on the East Coast. President Roosevelt woke to a ringing phone at 2:50 A.M. He picked up the receiver at his bedside and heard the voice of William Bullitt, the U.S. ambassador to France. Bullitt was calling with the news from Warsaw: Germany had invaded Poland. The president sat up. “Well, Bill, it has come at last. God help us all.” He lit a cigarette and started making calls, waking up the cabinet secretaries.

Later that morning Roosevelt called a quick press conference. The first question was, can America stay out of the war? Roosevelt said, “I not only sincerely hope so, but I believe we can.”

He was speaking for most of the country. In the days that followed, as Britain and France declared war on Germany, the U.S. public met the news with relief. Europe would defeat fascism on its own. The fight was across the ocean, far from U.S. shores. Nazis seemed a safe distance away.

In private, though, Roosevelt and his advisers were planning for the worst.

For years now, they had been thinking about the possibility of direct Nazi attacks on the United States. It was obvious that no effective invasion could be launched from Germany itself; ships were too slow, and airplanes couldn’t carry enough fuel to cross the ocean, drop bombs, and return home.

But there was a catch in this argument, an unnerving loophole: What if the Nazis got control of South America?

South America. It was neutral ground—for now. No government there had declared a position in the war. Brazil, Argentina, Chile, Paraguay, Bolivia, and Ecuador were content, for the moment, to sell beef and raw metals to the combatants and to measure the political winds.

But this would certainly change as the war evolved and politicians cut deals. Hitler had already shown an ability to destabilize foreign governments. That’s how Austria had fallen to the Nazis, and Czechoslovakia, too. And President Roosevelt was convinced that if Nazism took root in South America, even in just a few places, it would pose a clear and present danger to U.S. cities like New York.

South America was very big: the land mass of Brazil alone was slightly larger than the entire continental United States. South America was also very close: as Roosevelt put it in a 1940 speech to Congress, “Para, Brazil, near the mouth of the Amazon River, is but four flying-hours to Caracas, Venezuela; and Venezuela is but two and one-half hours to Cuba and the Canal Zone; and Cuba and the Canal Zone are two and one-quarter hours to Tampico, Mexico; and Tampico is two and one-quarter hours to St. Louis, Kansas City and Omaha.”

If Britain fell to Hitler, the thinking went, Nazi ships could move west and set up bases in South America, seizing its rich resources, the metals to make war machines and the food to sustain armies, and then U.S. coastal cities would be within reach of Nazi bombing raids. Some officials dissented from this view, namely at the State Department, which considered a Nazi invasion from South America to be unlikely, but the Reich’s rapid military victories and the erratic behaviors of the Führer had caused many to revise their sense of what was possible.

There was another sound reason to worry about German influence in South America. Millions of Germans were already living there as colonists. They had emigrated in waves since the late nineteenth century, seeking land and work, 140,000 arriving between 1919 and 1933 alone, many fleeing the same desperate economy that fueled the rise of the Nazis.

The Germans had left a cold country of worthless currency and sailed into the crystalline seas hugging a warm and open continent. A “bewildering abundance” met them ashore. “Everything is violent—the sun, the light, the colours,” the Austrian exile Stefan Zweig wrote of Rio de Janeiro, Brazil’s glinting capital. “The glare of the sun is stronger here; the greens are deep and full; the earth tight-packed and red . . . Rather than encouraged, growth has to be fought, so as to prevent its wild power from overwhelming the efforts of mankind.” In Rio the green leaves of palm trees burned white in the midday sun as if radioactive. Men wore suits of white linen that became soaked by sudden downpours and thunderstorms. Women strolled topless on Copacabana Beach. A cream-colored luxury hotel, the Copacabana Palace, faced the beach and the crystalline blue waters of the Guanbara Bay; Fred Astaire and Ginger Rogers danced in the hotel’s ballroom in the 1933 Hollywood musical Flying to Rio.

Some of the arriving Germans decided to stay in Rio; others filtered into the surrounding Brazilian provinces, sparse rural lands of forest and cattle, and still others scuttled south along the coastline to the fast-growing industrial city of São Paulo, which Zweig likened to Houston, Texas, because of its abrupt rise from nothing: “There are times when one has the sensation of not being in a city, but on some gigantic building site.” Farther south, another great city of the continent beckoned to the Germans: Buenos Aires, Argentina, a polyglot metropolis of four million, a chaos of automobiles and bookshops and neon lights and cobblestone streets where tango music descended from the open windows of brothels. The nation had grown rich from cattle and wheat raised in the Pampas, the flatlands to the west and south of Buenos Aires, where tens of thousands of Germans lived alongside the gauchos and their horses.

Wherever Germans settled in South America, they built German schools (two hundred in Argentina alone), German businesses, German radio stations, German newspapers, and transportation links back to the homeland. Zeppelins floated people and cargo from Berlin to Rio, and two airlines, Condor and LATI, connected South America and Europe. Condor was owned by Germans, LATI by Italians. A visiting U.S. consul reported “a fair sale for German Bibles” across three Brazilian states and that 20 percent of all residents spoke only German; parts of southern Brazil became known as Greater Germany. “The German spirit is ineradicably grounded in the hearts of these colonists,” wrote a German physician, “and it will undoubtedly bear fruit, perhaps a rich harvest, which will not only prove a blessing to the colonies, but to the Fatherland.” A German visitor to Brazil reported with pride, “Surely to us belongs this part of the world,” and the Nazi ambassador in Buenos Aires, Baron Edmund von Thermann, believed that German Argentines must show “complete subservience” to “the ambitions and desires of the home country. Germans naturally count on these prosperous nuclei to assist eventually in the rebuilding of a new Germany.”

A small percentage of German immigrants brought fascist politics to South America, starting local Nazi clubs and chanting Nazi songs, but these groups were small and disconnected, stagnant ponds of fascist fervor. The bigger rivers of fascist sympathy in South America coursed through the local populations. It was a time of protests, marches, fantasies of revolution. Right-wing parties and radicals on the continent found inspiration in Nazism. Followers of a Brazilian movement called Integralism raised their hands in Nazi-style salutes, wore uniforms of green (the men were “Green Shirts,” the women “Green Blouses”), and goose-stepped through the streets of Rio. In 1938, a throng of Argentine youths marched into the Jewish quarter of Buenos Aires, chanting anti-Semitic slogans, “stripped to the waist like Mussolini, mustachioed like Hitler,” writes one historian. “When enraged Jews attacked them, police arrested the Jews.”

Similar movements were gaining followers in Chile, Bolivia, and Paraguay, and powerful local officials poured fuel on the fires. Across the continent, men who dreamed of leading their own regimes had risen to the top of police and military hierarchies; many had gotten their training from German officers. A group of Paraguayan officers formed a secret lodge, the Frente de Guerra, to organize an ultra right-wing revolution; their motto was “Discipline, Hierarchy, Order.” The chief of the Paraguayan national police, wishing to honor the dictators of Germany and Japan, decided to name his son Adolfo Hirohito. In Argentina, a young military instructor with a Cheshire-cat smile, Juan Perón, was studying the leadership styles of Mussolini and Hitler and found much to admire. One Argentine general, Juan Bautista Molina, displayed so much zeal for National Socialism that even Thermann, the Nazi ambassador, found it “embarrassing.”

Hitler appreciated this wellspring of sympathy in South America. His strongest affinity was for Argentina, which had protected German interests in the First World War while ostensibly remaining neutral. In June 1939, three months before he invaded Poland, Hitler met with Argentina’s ambassador to Germany. Writes the historian Richard McGaha, “Knowing that war was going to break out soon,” the Führer “cryptically stated that he hoped Argentina would stay neutral and that neutrality could be the basis of a closer relationship.” Then Hitler launched into a tirade about America and England, saying that “the U.S. was the worst-governed country in the world,” that Roosevelt wanted war “at the instigation of the Jews, who controlled industry and the press,” and that England was “a paper tiger with its little fleet and meager air force.”

In his mind the Führer had already added South America to the Nazi column. If he decided not to invade at this time, he would simply annex the continent after defeating Europe. As Baron von Thermann put it, “Once the war were decided in Germany’s favor, her domination of Latin America would follow without much effort.” This was the Nazi attitude, and it meant that the war in South America could not be a hot war, a war of soldiers and sailors in recognizable uniforms, a war of battleships and mortars and planes and bombs. Instead it promised to be a war of languages and secrets, codes and conspiracies, masks and seductions, wireless transmitters and cipher machines—the type of war where everything depended on the invisible flashes of energy radiating from a radio coil hidden on a farm or beneath the floorboards of an unremarkable house.

The term of art for an intelligence operation that must remain entirely concealed is “clandestine.” If a clandestine job is successful, no one ever knows it happened. It is invisible. The war in South America would be the Invisible War.

There was a school in Hamburg where SS intelligence officers trained combatants for this war. Male party members were selected to receive a basic course in espionage tradecraft. They were taught to write letters in secret inks. The SS had developed a disappearing ink that actually looked like ink, bluish in color and carried in a regular ink bottle; a message written with this ink would turn invisible after a few minutes and could only be unmasked with a certain reagent. They learned how to operate a German-invented “microdot” camera that shrunk documents to the size of the dot above an i, allowing espionage reports to be concealed in otherwise innocuous letters, and they were shown different methods of writing messages in cipher, including an ingenious system for exploiting a popular novel, any novel, to generate garbled text.

For the purposes of spying, this hand technique was often preferable to cipher machines like Enigmas, which were bulky, harder to transport, and more incriminating if discovered. A novel aroused no suspicion. One in common use was All This and Heaven Too, a period potboiler about a French governess falsely accused of murder. Would the unlucky Henriette Desportes manage to clear her name? Or would the conniving Parisian judge dispatch her to the dungeon? German men abroad pressed their noses to the book, eyes wide, turning the pages quickly, underlining words—no, these were not Nazi spies, these were simply readers under the spell of a story, needing to know what happened next.

The SS instructors taught students how to transmit text in Morse code and how to operate shortwave radio transmitters and receivers. Radio technology had made giant leaps since the heyday of rum-running. A shortwave transmitter of moderate power could now fit in a suitcase. The transmitter was a small metal box with vacuum tubes on the inside and dials affixed to the cover, and the antenna was a long wire looped into a tight coil.

Portable transmitters in hand, the novice agents were dispatched to begin their espionage careers for the Führer. U-boats delivered some of the spies onto alien shores, and others parachuted from planes or sailed on neutral ships under phony names, sometimes getting caught by customs inspectors or police along the way, their radios confiscated. The SS issued all foreign spies two kinds of suicide drugs to ingest in case of arrest. The first was a tablet that caused death by heart failure within ten minutes, and the second was a powder that resulted in “a slow process of general collapse over a two-week period” when rubbed on the body.

If a spy managed to arrive at his destination with the radio intact, he unfurled the wire antenna and established contact with the fatherland, tapping out an encrypted message in the dots and dashes of Morse, the signal aimed at a receiving station in Hamburg or Berlin. Sometimes it worked, and the spy could be heard in Germany—there were no atmospheric disturbances, and the signal squeezed through the crowded frequencies—but storms and interference often fuzzed out the radio pings, making it necessary to build more powerful stations, which required a higher level of expertise. A Funkmeister was needed: a technical leader, a radio wizard, able to piece together clandestine radio transmitters in foreign lands. And this is why, in 1941, the Nazi SS dispatched its most capable Funkmeister, Gustav Utzinger, a twenty-six-year-old man with short brown hair and a chemistry Ph.D., to South America.

Elizebeth Friedman’s next mission for America became the biggest secret of her life. She would never speak in detail about what she did between 1940 and 1945, even as an old woman, and the records of her work, the documents that now make it possible to tell the story, were classified after the war and locked away for a generation, unsealed only after her death. In the 1950s and 1960s, when she gave speeches or interviews about her career, she freely shared anecdotes about various colorful adversaries of the past—the millionaire George Fabyan, the rumrunners, the drug smugglers—but she skipped the Second World War entirely. These were the years when she disappeared into “a vast dome of silence from which I can never return,” she said.

The one time she seems to have alluded to her wartime mission, briefly and vaguely, was in 1975, during an interview with her husband’s biographer. She uttered a few words and then the transcript cut off.

“The spy stuff,” she said. “That’s what I did.”

It wasn’t Elizebeth’s conscious decision to spend the war chasing Nazi spies. It was yet another “pure accident” in her career. This is how it always happened: She put her ear to the ground here and there to learn how the pieces of the world fit together. She figured out how to hear a new sound. Then men in uniform showed up at her side, asking questions, wanting to listen over her shoulder. This had been true at Riverbank two decades earlier, when “the world began to pop and things began to happen,” as she put it once; it was true in the 1920s and ’30s when she shone a floodlight on the American criminal underworld; and it was proving true again now, in early 1940, when she and her team identified a new and sinister set of voices in the intercepts furnished by the listening stations.

The basic rhythm of her typical weekdays had not changed since the early ’30s. She was still working in her coast guard office at the Treasury Annex building near the White House, serving as chief of the Cryptanalytic Unit that she had founded in 1931 and nurtured ever since. Her three junior codebreakers, Robert Gordon, Vernon Cooley, and Hyman Hurwitz, the ones she had originally recruited and trained, were still with her, and a handful of women clerk-typists had also joined the team as support staff. Elizebeth, Gordon, Cooley, and Hurwitz often worked together at a long table in the office, analyzing the ever-replenishing piles of cryptograms that arrived from the coast guard listening stations, chewing the ends of their pencils, maps of the world pinned to the wall behind them, the clack of the clerks’ typewriters filling the room.

Outside the door, they could hear the muffled noise of T-men going this way and that, customs men, narcotics men, IRS men, coast guard men. They pressed their foreheads to the intercepts, Elizebeth perhaps wearing a simple white high-collared dress, Gordon smoking a pipe in a suit and vest, chomping on the pipe and frowning at a page. Sometimes Elizebeth would stand up and disturb Gordon’s cloud of smoke as she walked to a shelf to look at a piece of cryptologic literature or to examine one of the cipher machines she kept there in case she should encounter a message that had been generated by one. She had an Enigma machine on the shelf, an old version that had been freely available in the 1920s. She also had a Kryha there, the semicircular German device that William had once mastered.

Elizebeth reported to the chief of the coast guard communications section, a salty vice admiral named John Farley, and Farley reported to the secretary of the Treasury, Henry Morgenthau Jr., an old friend of President Roosevelt from a prominent Jewish family. Morgenthau was the kind of person Elizebeth tended to get along with—polite, educated, pragmatic—although Elizebeth came to dread phone calls from his devoted personal secretary, Henrietta Klotz, who had a habit of calling Elizebeth’s office at 4:28 or 4:29 P.M., one or two minutes before the 4:30 close of the day, and making what Elizebeth called “rapid-fire dictator-sort of requests,” demanding that Elizebeth and her team solve some difficult problem in an impossibly small amount of time. Morgenthau would usually phone Elizebeth the next day and reverse Klotz’s order with bashful apologies.

Morgenthau needed Elizebeth to be happy. He now depended on her to perform one of the department’s wartime functions. Smuggling wasn’t what it used to be—the war had disrupted the drug networks and made business perilous—so Elizebeth’s Cryptanalytic Unit had shifted its attention to British and German ships. The Treasury was responsible for enforcing U.S. neutrality laws, and foreign ships along the East Coast needed to be monitored for any violations that might cause diplomatic controversies. At Morgenthau’s request, in 1938, the unit began to analyze the wireless messages of British cruisers and German merchant vessels. Elizebeth broke the codes of Nazi captains as they tested the limits of U.S. neutrality and provoked tense confrontations. In December 1939, a German freighter flying the swastika flag pulled suspiciously close to Florida shores and was chased by U.S. Army planes and a nearby British cruiser, Orion. Elizebeth decrypted the German captain’s panicked messages home. It was the first gunfight of the war in American waters:

AM TRYING TO RUN INTO AMERICAN HARBOR PORT EVERGLADES OR MIAMI CODE DESTROYED

THE CRUISER HAS TRAINED HIS GUNS AGAIN HE IS RUNNING SLOWLY FORWARD

CRUISER NAMED ORION

THREE AMERICAN ARMY PLANES HOVERING OVER US

“Exciting, round-the-clock adventures,” she said later about these episodes. But an even more intense mission was yet to come.

While monitoring these radio signals for her Treasury bosses and solving the puzzles that were given to her, Elizebeth started to detect a new import to the messages. In January 1940, with Hitler preparing to invade Scandinavia, dozens of mysterious encrypted texts piled up in Elizebeth’s office all at once, apparently transmitted by several different unregistered radio stations and intercepted by U.S. listening stations.

At first, the messages looked similar to the thousands of smuggling messages she had solved before. They used the same kinds of call signs and similar frequencies. But after a brief period of confusion, Elizebeth realized that the messages hadn’t been sent by smugglers at all. The plaintexts were in German. They contained sensitive information about the routes of U.S. and British ships and the capacities of U.S. factories. And according to the bearing fixes, the signals originated from unknown radio stations in Mexico, South America, and the United States.

It soon became clear that the stations had been built by Nazi spies to share sensitive information with their bosses in Germany, transmitting and receiving dots and dashes of encrypted text at the speed of light. A pair of stations exchanging wireless signals formed a “circuit,” and each circuit was protected by a different code or cipher that had to be broken before the messages could be read.

These were clandestine circuits, meant to stay invisible, and it became Elizebeth’s goal to pry them out of the dark while remaining invisible herself—an essential part of the job. She knew that if the spies discovered that she was breaking their codes and reading their messages, they would switch to more secure codes, and she wouldn’t know what the spies were saying until she could break the new codes, which might take weeks or months. A spy who speaks in a broken code is “the goose that lays the golden eggs,” as William put it once. If you want to keep gathering the eggs, you must not frighten the goose.

For this reason, Elizebeth’s Cryptanalytic Unit “was probably even more secret than other [codebreaking] organizations,” the NSA concluded after the war, “because it dealt with counterespionage.” Counterespionage, counterintelligence—these are the formal terms for what Elizebeth was beginning to do. She was counterspying on foreign spies, serving as America’s eyes and ears in the invisible world of fascist espionage. Today there are large sections at CIA and FBI that perform foreign counterintelligence, teams of American professionals who spend their days trying to monitor the activities of Russian and Chinese spies, but in 1940 there was almost nothing, and Elizebeth had to act with extreme caution every day. It was essential that her Nazi targets never learn that she existed.

The first few batches of eggs fell smoothly into her basket. As soon as Elizebeth began to analyze the clandestine circuits in 1940, she realized that the spies were relying on different kinds of hand ciphers, variations of tried-and-true methods. Some were familiar systems from the rum days, adulterations of commercial codes like the ABC code and the ACME code. These were solved in a snap. The key for one circuit was found to be 3141592, the first seven digits of the mathematical constant pi. Elizebeth called this circuit “the pie circuit.” Sometimes the Germans sent the key at the start of the message and in groups of three or four letters instead of five, indicating that there was something special about these letters and giving away that they were a key.

When an unfamiliar system was encountered, and nothing was known about the speakers “to provide an entering wedge,” Elizebeth and her teammates tried to start with something small and simple. For instance, if they determined by a routine sort of check that they were dealing with a transposition system, with the letters mixed up instead of swapped out, they would look for common German words in the messages, like zwo, “two,” which is a useful word to a codebreaker because it contains two low-frequency letters, z and w, which makes it stick out more. (The names of numbers were often spelled out in messages to eliminate potential confusion from dropped letters due to radio interference.) Another technique that often helped was to take multiple messages and stack them on top of one another, creating a “depth” of text that made it easier to identify patterns as opposed to analyzing one message at a time:

1	E	A	W	I	Z	T	Z	N	X	O
2	I	E	U	R	Y	R	X	F	E	H
3	U	I	U	H	Z	F	E	N	N	X

Here, Elizebeth was able to look at row 1 and anagram the letters, Scrabble-like, to make the word zwo:

1	Z	W	O
2	X	U	H
3	E	U	X

Now the columns were in a different order, and this new order gave a clue to the structure of the underlying cipher that allowed her to break it.

Essentially, Elizebeth’s goal was to look at these daunting mountains of nonsense and chart a route up the slope in small discrete steps, each of which was like a little game—not quite child’s play but not totally unlike child’s play, either. And the games grew more intricate as the months went on and the coast guard codebreakers followed the intercepts.

Several sets of Nazi spies were using book ciphers similar to the ones that Elizebeth and William had long studied but with new twists. For instance, on January 1, 1940, she received her first intercept from a wireless circuit that linked Mexico with a radio tower in Nauen, Germany. The messages contained only eleven letters of the alphabet: N, R, H, A, D, K, U, C, W, E, and L. One message began

UHHNR

LNDAL

NURND

WCNCK

NRHLN

DNRAN

CHNDR

UNDEN

Relying on intuition and experience, Elizebeth made a few quick assumptions. N was the most frequent letter. She guessed it was being used as a “word separator”—a space bar. She also guessed that because there were only eleven letters in the messages, one of which was a space, the letters must stand for the numbers 0 through 9. But which letters stood for which numbers? If she was correct, the spies might have used a key word to determine that. Elizebeth and her colleagues tried to find the key word by anagramming the eleven letters:

WACKELND  RUH

WAHL  DRUCKEN

ACH  RUND  WELK

DA  LUNCH  WERK

DURCHWALKEN

There it was: Durchwalken, a colloquial German word meaning “to give a good beating.” This was probably the key:

D	U	R	C	H	W	A	L	K	E	N
1	2	3	4	5	6	7	8	9	0	–

Now Elizebeth was able to turn the letters of each message into numbers, using N as the separator:

UHHNR	LNDAL	NURND	WCNCK	NRHLN	DNRAN	CHNDR	UNDEN
2 5 5 - 3	8 - 1 7 8	- 2 3 - 1	6 4 - 4 9	- 3 5 8 -	1 - 3 7 -	4 5 - 1 3	2 - 1 0 -

Cleaning up the numbers, the line became

255-38

178-23

164-49

358-1

37-45

132-10

This looked like a book cipher to Elizebeth; the numbers probably corresponded to locations in some unknown book owned by the spies. After translating the letters of several messages into numbers, she saw that some number combinations appeared more frequently than others: 1-1, 132-10, 343-2, and 65-12. The coast guard codebreakers underlined these frequent combinations, and “after a little experimenting the following was produced”:

65-12	132-10	373-2	301-21	285-25	343-2
B	E	R	L	I	N
65-12	375-2	132-10	321-2	132-10	343-2
B	R	E	M	E	N

BERLIN and BREMEN, two German cities. (In some cases, a letter like R was linked to a few different number combinations.) These frequent letters gave her a start, and when able to solve the code in full, Elizebeth identified the names of two known Nazi agents in Mexico, MAX and GLENN, who would appear in other messages in the future, linked to agents in the United States and South America. The two Nazi spies were reporting to Berlin on the movements of U.S. and British ships, making those ships vulnerable to U-boat attacks.

Elizebeth solved their book cipher without needing to see the book and did the same with messages that used other books: The Story of San Michele, the memoirs of a Swedish physician; Soñar la vida, a spy story by a female Mexican fascist; O servo de Deus, a Portuguese novel. One Nazi spy proposed using the 1936 novel Vom Winde Verweht—in English, Blown Away by Wind, i.e., Gone With the Wind—and asked Berlin to locate a copy. Berlin replied that Blown Away by Wind was unavailable in Germany and another book would need to be chosen.

Several Nazi agents, Elizebeth discovered, were using a copy of the romantic novel All This and Heaven Too and a sophisticated process that generated messages full of garbled letters instead of numbers. Each spy had been assigned a unique identification number, such as 7. To encrypt a message, the spy would take that day’s date, add the number of the day and the month to his identification number (for a January 10 message he would add 1 + 10 + 7 = 18) and turn to the resulting page in the novel (page 18). The first words of the first line became part of that day’s key—the key for transforming plaintext words into blocks of nonsense according to a Scrabble-like method that jumbled the letters by stacking them into columns. The rest of the key was taken from the first letters of unindented lines going down the page.

To solve the messages, Elizebeth first had to deduce that All This and Heaven Too was the novel these particular spies had chosen. To do this she went through the same process of reverse engineering that she and William applied in 1917 to solve the Hindu messages. Then she bought her own copy of All This and Heaven Too and kept it on her coast guard desk, allowing her to easily ungarble any new message sent with that system, flipping through the novel and underlining or circling the pieces of the daily keys in red pencil. Here is how she marked up page 15, where the novel’s fictional heroine is deciding whether to become the governess for a hot-tempered Parisian family and move into their home:

Yet she did not dread the thought of entering it. The difficulties t presented would at least be stimulating. One would not erish of boredom in a place where charges of gunpowder might urk in unexpected corners to explode without warning. She felt ddly exhilarated—almost, she thought, as if she were about to tep upon a lighted stage filled with unknown players, to act a ole she had had no chance to rehearse beforehand. She must find he cues for herself and rely on her own resourcefulness to speak he right lines. Henriette Desportes’s heart under the plain gray

Elizebeth wrote the letters of the key horizontally on a piece of graph paper and used it to fill in the German plaintext.

Her basic puzzle-solving style hadn’t changed from the smuggling days, and it remained effective: a process of trial and error with pencil and paper, deduction and experimentation, granules of eraser dust swiped away with a flick of the palm. Her scrap papers still looked like the scrap papers of a person doing the newspaper puzzle page over Sunday-morning tea; she wrote no equations, only numbers and letters grouped and stacked in rows, columns, squares, rectangles, and more exotic shapes. This approach worked for her because over the previous twenty-five years, encountering tens of thousands of messages, Elizebeth had solved so many different kinds of puzzles that she knew how to find shortcuts, to identify patterns in fields of text that were like signatures telling her what to do next. She was a kind of human computer in this sense. Today, if you want a computer to recognize certain patterns, you can train it through a process of “machine learning.” How do you get a computer to recognize a picture of a cloud, for instance? You feed it a lot of pictures and say, essentially, This here is a cloud, and This here is not a cloud. After the computer gains enough “training data,” it’s able to look at a new image, do some math, and say, This is almost certainly a cloud. By 1940, Elizebeth’s brain had probably accumulated more training data about codes and ciphers than any other brain on the planet. She had just seen so many damn clouds. It’s why she was able to make inspired guesses about puzzles. She may not have been writing equations, but she was thinking mathematically.

This is also why, in 1940, when Elizebeth encountered her first Enigma messages from a German Enigma machine, she didn’t feel overly intimidated.

Enigma was a straightforward idea expressed in a diabolical device. In the simplest sense, it was a box that cranked out poly-alphabetic ciphers. Remember the secret messages that eight-year-old Barbara Friedman sent her parents from summer camp? A=B, B=C, C=D. That’s a MASC, a mono-alphabetic substitution cipher. One cipher alphabet encrypts the whole message. Enigma was poly instead of mono, using multiple cipher alphabets per message.

Poly-alphabetic ciphers date to the sixteenth century and can be written by hand with the aid of pre-printed grids of letters or sliding strips of paper. Instead, Enigma did the job with three or more rotating alphabet wheels connected to electrical wires. The wheels lived inside a box with a typewriter keyboard on the outside, the keys arranged in a familiar order, starting with Q W E R T Z U I O. Above the keyboard was a “lampboard” of the same twenty-six letters in the same order. When a writer pressed a key, such as Q, a different letter, perhaps Z, would illuminate on the lampboard—the cipher letter, lit by a small battery-powered bulb. Later, the recipient of the message, operating his own identically configured Enigma, would type Z, and Q would light up, decrypting the message letter by letter.

With each key press, an electrical circuit was completed, and Enigma stepped the right-hand wheel, shifting it one letter forward. Once the wheel stepped through all letters, it stepped the middle wheel by one letter, then the left-hand wheel. The motion was similar to a car odometer—after you drive 9 miles, the right-hand number flips to 0, and the next number to the left flips to 1—and it generated a seemingly random, nonrepeating sequence of 16,900 cipher alphabets before the three wheels returned to their starting positions.

Crucially, no letter could be enciphered as itself. If you pressed j a million times, you would never see j light up on the lampboard.

Although this was a known limitation of the machine, it seemed to pale in comparison with Enigma’s flexibility. The wheels could be arranged in different orders (1-3-2, or 2-3-1), the alphabet rings on the wheels could be set at different starting positions on the wheels, and the starting letter of each wheel, as seen through a small window on the box, was another variable. The choice of variables comprised the machine’s key—the starting configuration used to encrypt all messages on a particular day, week, or month, depending on how often the key was changed.

How many possible keys existed? Depending on the model of Enigma, the number of keys might be as large as 753, 506, 019, 827, 465, 601, 628, 054, 269, 182, 006, 024, 455, 361, 232, 867, 996, 259, 038, 139, 284, 671, 620, 842, 209, 198, 855, 035, 390, 656, 499, 576, 744, 406, 240, 169, 347, 894, 791, 372, 800, 000, 000, 000, 000.

Each one of these keys produced a unique set of 16,900 alphabets before repeating.

All of this seemed to make the job of a codebreaker impossible. There were too many possibilities to comprehend, and then there were possibilities about those possibilities, and possibilities about those possibilities about those possibilities. Clearly, shortcuts had to be discovered, and by the late 1930s, finding these shortcuts—and conquering Enigma—was the biggest problem facing Allied intelligence. After Polish mathematicians made some early breaks into the device, the Germans kept changing its design and how it was used, so the battle over Enigma was ongoing, a cryptologic arms race. The machine had been clunky at first, weighing as much as one hundred pounds, but subsequent versions grew lighter and more compact. The German navy, the Kriegsmarine, first adopted them in 1926 and installed Enigmas in ships and U-boats, followed by other branches of the military, embassies, and intelligence services. In 1936, the Nazis banned all commercial sales of Enigma and began to improve the machine in secret, adding additional components and subtleties intended to make Enigma codes absolutely unbreakable. Different Nazi organizations developed their own variants. Germany withheld knowledge of these alterations from the enemy, as if Enigma were a submarine or a bomb.

To extract useful intelligence from an Enigma system, Elizebeth Friedman (or anyone else) needed to accomplish two separate and immensely difficult things. First, the machine itself had to be “solved,” its inner workings deduced and mapped—the motions of its wheels and the maze of wires controlling them. This required some leap of human ingenuity, some feat of mathematical deduction or inspired guessing. Then, once the wiring was solved—the part of the system that generally didn’t change—the keys had to be recovered, which changed at different intervals (month, week, day) depending on the practices of different Nazi services. If you found an Enigma key in the morning, you might go to bed at night and get locked out again in your sleep, and the next day you had to find the key again if you wanted to read the new day’s messages.

There were too many Germans using too many Enigmas with too many shifting keys to ever recover the keys by hand, so codebreakers needed to build machines of their own to assault the enemy’s machines, giant electro-mechanical contraptions and some of the first digital computers, too. Automation. Polish codebreakers were the first to solve Enigmas and automate the process of recovering keys. They built “bombes” that mirrored the Enigma rotors, ticking through possible alphabets until they found ones that might fit. Later, the British mathematician Alan Turing discovered how to make bombes dramatically more powerful, based on mathematical principles and previously solved bits of text known as “cribs”—a crib might be the name of a Nazi officer, the time of day, or “Heil Hitler.” His solutions were essentially search algorithms, ancestors of the Internet search algorithms of today. Turing’s biographer calls these “search engines for the keys to the Reich.” It was anti-Nazi Google.

The British codebreakers worked at Bletchley Park, a mansion in the countryside outside of London. Bletchley grew from a handful of people in 1938 to thousands by 1945, the bulk of them women, recruits from the Women’s Royal Navy Service who operated the bombes, among other jobs, and were billeted in large country houses.

The Enigma codebreaking program would come to be known as ULTRA; Enigma decrypts were stamped with the imposing phrase TOP SECRET ULTRA as a reminder to handle them with the utmost care. Later, America would join forces with the British, assembling its own ULTRA factories in Washington and sharing the burden. But early in the war, when Elizebeth and her coast guard unit analyzed their first Enigma machine, ULTRA was a strictly British franchise. There was no one to tell the Americans what to do. They had to invent their own method.

At first, Elizebeth didn’t know that she was dealing with an Enigma at all. Enigma cryptograms look like lots of others, generic blocks of nonsense letters. In January 1940, coast guard radio monitors began intercepting one to five messages per day with the call signs MAN V NDR and RDA V MAN. Elizebeth wasn’t able to make heads or tails of the first twenty or thirty messages that were intercepted on this circuit. However, after accumulating a greater “depth” of messages, sixty or seventy, she was able to write them one on top of another on a worksheet and see the letters in a new way by gazing down the columns.

Enigma is poly-alphabetic. It creates a new cipher alphabet with each key press. That’s the beauty of the machine. But if an Enigma user types a number of messages using the same starting position of the rotors, the first letter of each message will use the same alphabet—and the second letter of each message will use the same alphabet, and the third letter. In other words, any individual message is full of alphabets, but if a codebreaker lines up the messages in a tower, each column in the tower is mono-alphabetic—one alphabet:

1	2	3	4	5	6	7
D	X	J	X	L	H	N	. . .
L	W	S	X	I	Y	F	. . .
M	H	O	S	S	L	C	. . .

The letters in the first column here, D L M, all use the same alphabet. And the letters in the second column, and so on.

With only three messages, there isn’t enough information to help the codebreaker. The “depth” is too low. There need to be more floors in the tower. At greater depths, closer to twenty messages and beyond, letter frequencies become visible:

1	2	3	4	5	6	7
D	X	J	X	L	H	N	. . .
L	W	S	X	I	Y	F	. . .
M	H	O	S	S	L	C	. . .
M	A	P	A	C	T	Y	. . .
F	P	W	S	G	S	C	. . .
Y	Q	A	S	A	C	W	. . .
N	S	H	W	U	F	C	. . .
F	U	W	X	G	S	P	. . .
M	B	D	W	X	U	O	. . .
O	P	O	D	Y	X	L	. . .
A	J	Y	S	X	F	D	. . .
M	W	S	X	E	C	C	. . .

M appears four times going down column 1. In this column, M might be equivalent to the letter E, the most frequent letter in German as well as English. In other columns, different letters might be equal to E. And now the codebreaker can use tried-and-true methods to fill in plaintext letters and piece together the adversary’s words.

In this way, the technique of “solving in depth” can take a hard problem and turn it into a simpler problem. The trick is often to get the messages aligned in depth in the first place. If the Enigma user changes the starting position of the rotors from message to message, the floors of the tower have to be staggered to track with the shift in the starting position.

Figuring out how to align messages in depth is a subtle art. It can be done with clever guesswork and trial-and-error, and it can also be done by applying the principle of the Index of Coincidence, William Friedman’s fundamental insight about the relationships between letters that sit in towers of text. Elizebeth tended to use both approaches in her work, but luckily, in this case, she didn’t need to align the messages, because the senders had made a mistake by using the same starting position for all the messages. The messages were already in depth. Before long, then, the coast guard codebreakers were able to identify frequent letters in the columns and use those letters to piece together the plaintexts for most of the first batch of messages.

The words seemed to be in German.

Elizebeth and her colleagues still didn’t know what type of cipher they were dealing with, so now they decided to write down the alphabets for many of the messages they had solved in depth, the ciphertext equivalents of the plain letters, to see if a pattern popped out. They quickly noticed that no letter was ever enciphered as itself: an A never meant A, a B never meant B. This suggested an Enigma.

They went to the shelf in their coast guard office and picked up their old commercial Enigma machine.

The codebreakers had already solved most of the messages, but now they wondered if they could solve the machine itself—the wiring. Knowing the wiring makes it easier to solve new messages. Without the wiring, they would have to repeat the laborious process of solving in depth every time the key changed. Their challenge now was to use the text they had recovered, the plain letters and the cipher letters, to work backward toward the unknown machine, almost like a police detective analyzes the spatter pattern of blood at a murder scene, starting with the red evidence and rewinding back to the moment of the crime, deducing from the crusts of blood the speed and angle of the knife.

Unbeknownst to the coast guard, groups of British and Polish codebreakers working on the Enigma problem had already discovered methods for working backward from the text to the machine. The Poles had done it with an algebraic approach, the mathematics of permutations, and one of the brilliant Bletchley codebreakers, a linguist and scholar of classical literature named Dilly Knox, had relied more on pattern recognition and a kind of alphabetic grid called a “rod square.” But the coast guard didn’t know about these approaches, and so, working in isolation, the codebreakers had to grope toward their own method. They poked and prodded and turned the wheels; they wrote alphabets on sliding strips of paper and moved the strips against one another, thinking.

It seemed to Elizebeth that there must be a fixed relationship between the alphabets she had already discovered by solving in depth—the plaintext letters and their cipher equivalents—and the motions of the Enigma’s wheels. To test this hypothesis, she drew a number of diagrams that visualized the relationships between letters at each position of the machine. She wrote new kinds of towers of letters on the worksheets that were more like X-rays than photographs, probing more deeply into the identities at the heart of the Enigma, and immediately she saw clear patterns, hints of order and regularity.

Certain letters repeated vertically on the page, like LL and HH, and also pairs of letters, like SJ and EM. Elizebeth and her colleagues realized that these letter groups were telling them something about the spacing between pairs of wiring contacts on the Enigma’s rotors. The maps were whispering secrets about the physical intricacies of the machine. Building upon these “remarkable results” over the following days, filling more worksheets to the brim with letters, drawing more towers and analyzing the patterns that appeared, the codebreakers managed to solve the wiring for all three wheels of the unknown Enigma. Then they were able to reveal the full plaintexts of all unsolved messages from the radio circuit.

The codebreakers now realized two slightly disappointing facts: The plaintexts seemed to contain no Nazi secrets; later the codebreakers learned that the messages had been sent by the neutral Swiss army, which sometimes used Enigmas to communicate in German. Then the coast guard shared the wiring diagram of the Enigma with William’s codebreaking team at the army, in case it might be useful to them, and the army reported back that the diagram corresponded exactly to the wiring of a commercial version of Enigma.

Elizebeth had hoped that she was mastering a new kind of Enigma entirely. Still, it was a significant achievement. “This recovery of wiring assumed to be unknown was achieved without prior knowledge of any solution or technique and is believed to be the first instance of Enigma wiring recovery in the United States,” her team wrote in a secret technical memo after the war. As far as Elizebeth and her codebreakers could tell, and they were hardly prone to bragging, they were the first Americans to solve an unknown Enigma.

Until this moment, cipher machines had always been William’s territory, not Elizebeth’s, but her solution of the commercial Enigma showed that she had a similar aptitude for solving machines, and this initial headfirst dive into the pool of Enigma codes would lead her to deeper waters later in the war. Of course, she didn’t know this in early 1940. Demolishing that first Enigma was just work. She was confident enough in her abilities that solving an Enigma seemed like a reasonable and normal thing that she might accomplish with her team on a given week. She didn’t brag or make a big deal. Anyway, there was no time. New puzzles were arriving at the coast guard all the time, new codes to break, along with increasing demands for assistance from outside agencies.

All along her plaintexts had been circulating through other parts of government. Each time her unit solved a message, a clerk typed the English solution on a fresh sheet of paper, a decrypt, and gave it to the coast guard chief of communications, Vice Admiral Farley, for dissemination. Depending on the content of the decrypt, the vice admiral might send a copy to navy intelligence (OP-20-G), army intelligence (G-2), the State Department, British intelligence, or the FBI. The decrypts were like blood cells in the veins of government, delivering the vital oxygen of raw intelligence, and as different intelligence agencies realized that Elizebeth had tapped into a trove of information about Nazi spies, they inevitably asked the coast guard for more decrypts. In the 1920s, she had complained about government men “appearing on my doorstep,” wanting her to solve puzzles. They were still appearing on her doorstep, but now, instead of relatively anonymous T-men, they were some of the most powerful spymasters in the world.

J. Edgar Hoover liked to eat dinner at Harvey’s restaurant on Connecticut Avenue, next to the Mayflower Hotel, a five-minute walk from his suite of offices in the Department of Justice headquarters, a gargantuan gray edifice near the National Mall. Harvey’s had separate dining rooms for men and women. The ladies’ dining room was on the second floor, accessible by a separate entrance at street level. The first floor was the gentlemen’s restaurant and bar, with waxed floors and rich leather banquettes. It was one of those places in Washington where men of influence slurped oysters and let their guard down for an hour or two.

The FBI director’s face was beginning to acquire some of the first creases and pouches that would characterize the eventual marble busts of him. He was forty-five years old, one of the few immutable objects in an ever-changing city. He wore white shirts, double-breasted Brooks Brothers suits, and a hat with a brim that could be turned up or down. His agents wore the same uniform. A pink expanse of forehead separated his bushy black eyebrows from his thinning hair. The large neat desk back at his office, a corner office on the fifth floor of Justice, contained a radio, usually a vase of fresh flowers, and a framed copy of “Penalty of Leadership,” the text of a Cadillac advertisement from 1915. It read in part, “When a man’s work becomes a standard for the whole world, it also becomes a target for the shafts of the envious few.”

At Harvey’s he usually ordered steak or roast beef and a Caesar salad. He ate at the same table every time, the most secure in the room, almost invisible from the door under a stairway. A reporter once watched Hoover sign twenty autographs during a single dinner at Harvey’s. He liked to sit there with his chief deputy, armed bodyguard, and longtime companion Clyde Tolson. It was a table for four with just two chairs. There was always a bottle of wine waiting for Hoover at his table when he arrived—part of a ritual that he performed here.

William Friedman dined at Harvey’s on occasion. There were times at the restaurant when the cryptologist sensed motion in his peripheral vision, when a shadow darkened the white cloth. He turned his head and saw Hoover standing there with the bottle of wine. Without saying a word, the director nodded and poured wine into the cryptologist’s glass. He had respected William for years and appreciated his periodic assistance with FBI cases, with the little encrypted notes written by criminal suspects that William would solve in his free time and send back to the bureau.

Hoover was almost certainly aware of Elizebeth Friedman. But he would not yet have had many chances to cross her path. She wasn’t allowed to eat in the gentlemen’s dining room at Harvey’s. There were a lot of male enclaves like this in the city, inaccessible to her. And Hoover was a chauvinist of the old school. When he first took charge of the bureau in 1922, there had been three female agents. He got rid of them. The next two female agents wouldn’t join the bureau until after his death in 1972. He argued that women weren’t agent material because they couldn’t be taught to shoot guns. Female clerks and secretaries at the bureau had to wear skirts and weren’t allowed to smoke at their desks as the men could. One of his least favorite people was Eleanor Roosevelt, who wrote him a mildly indignant letter after the FBI conducted an intrusive background check on one of her friends. Hoover compiled a secret dossier alleging she was a communist. “When a woman turns professional criminal,” he wrote once, “she is a hundred times more vicious and dangerous than a man.” Women at Hoover’s bureau were only deemed fit for “boring clerical functions,” according to the memoir of one longtime agent. “It was perfectly all right to bullshit ’em and ball ’em: Just don’t tell ’em any secrets.”

But by 1940 Hoover had gotten himself into a jam serious enough to require the technical assistance of a woman.

It had long been the FBI’s job to disrupt espionage rings within U.S. borders. Any Nazi spies operating in America were Hoover’s quarry. However, he didn’t seem to be very good at catching them. He had built the bureau’s name on its flashy investigations of jazz-age gangsters, men who enjoyed attention and went out in public with entourages. Counterespionage was another discipline entirely, a matter that required a certain finesse, and the bureau’s first sizable Nazi spy case, in 1938, had ended in a public-relations disaster.

That year in New York, the FBI arrested a Chicago man of Austrian parentage, Guenther Rumrich, along with two associates suspected of spying for Nazi Germany. Then an FBI agent named Leon Turrou made the mistake of tipping off Rumrich’s collaborators that an indictment was coming. They panicked and fled the country.

Newspapers mocked the FBI for letting Nazis slip through its fingertips, and U.S. intelligence agencies that had long resented the FBI found new reason for their scorn. Over the years, Hoover’s insatiable hunger for publicity had caused a lot of bad blood; in the press he repeatedly claimed sole credit for investigations to which other agencies had contributed but were not free to discuss. The head of army G-2, George Strong, one of William Friedman’s superiors, despised Hoover, and the navy OP-20-G chiefs couldn’t stand him, either. Henry Morgenthau at the Treasury hesitated to even speak the director’s name in meetings, and Hoover thought of him as “that Jew in the Treasury.” When British intelligence officers started to arrive in Washington in 1940, hoping to forge links with U.S. agencies, they were shocked by this toxic atmosphere of mistrust and quickly traced the cause to Hoover. “J. Edgar Hoover is a man of great singleness of purpose, and his purpose is the welfare of the Federal Bureau of Investigation,” a group of British operatives later wrote. “It was once remarked of a well-known Oxford scholar that, while he had no enemies, he was hated by all his friends. Something of the same kind would express the feelings towards the FBI of its fellow U.S. agencies.”

For a man as vain as Hoover, and as publicity-obsessed, and as intensely disliked by rivals in his own government, the bungled Rumrich case represented both a personal black eye and a threat to the FBI’s future authority. Somehow he needed to salvage the bureau’s reputation, to prove that it was capable of catching fascist spies, and in 1939, he proposed a bold plan to do just that.

Hoover knew that the concept of “hemisphere defense” had become a fixation with Roosevelt and military chiefs: Guarding the United States meant guarding the entire Western Hemisphere from Nazi encroachment. In other words, it wasn’t enough to fortify U.S. defenses. South America must be protected as well. Roosevelt talked about hemisphere defense in speeches, arguing that “no attack is so unlikely or impossible that it may be ignored,” and Secretary of the Navy Frank Knox raised the specter of Nazi planes taking off from South American airfields in the night and dropping bombs on “our own women and children in our teeming seaboard cities.” Seeing an opening, J. Edgar Hoover pressed Roosevelt to dramatically expand the FBI’s jurisdiction. For the sake of “the common defense of the Western Hemisphere,” Hoover argued, the FBI must be allowed to operate beyond U.S. borders. He demanded the authority to send men into South America, “to seek out and identify agents of the Axis operating in all the Americas, to ensure the ultimate safety of the United States.”

Hoover got his wish in June 1940, with a presidential directive that represented a historic expansion of the FBI’s power. For the first time, the bureau was free to dispatch agents into other countries. He created a new division called the Special Intelligence Service (SIS) and began recruiting agents for duty in South America.

Their mission would be to find and monitor the secret mail drops and radio stations used by the spies; to map the structure of their organizations and communications networks; to determine the true identities of the enemy agents; and to cooperate with local State Department officials and police in arresting the spies, seizing the radio stations, and destroying the rings.

A tall order. The first five SIS agents were dispatched to the continent in September 1940, one each to Peru, Uruguay, Argentina, Brazil, and Venezuela. Pale and corn-fed, they stepped off their planes into the lacerating sun of another continent. They wore snap-brim hats and looked like detectives that South Americans had seen in newspapers and movies. The agents knew little about codes, ciphers, or radio, these crucial tools of their adversaries, and didn’t speak the local languages. The SIS man sent to Brazil had been given a crash course in Spanish. When he arrived, he realized, to his frustration, that the language of Brazil was actually Portuguese.

Hoover’s men in South America were so unprepared that they had almost no chance of catching the spies through old-school gumshoe tactics: interviewing associates, recruiting confidential informants, developing leads. They needed to know what the spies were saying to one another in private. They needed codebreaking. And this was exactly the problem.

To break codes, you need intercepts and you need codebreakers to solve the intercepts. The FBI had neither. It had no intercepts because it had no listening stations; when the bureau wanted intercepts it was forced to obtain them from the coast guard and the Federal Communications Commission (FCC). And when the FBI got these intercepts, it couldn’t read them, because the FBI had no codebreaking unit. What it had instead was a Technical Research Laboratory, essentially a crime lab, a place where bureau technicians analyzed bullets, fingerprints, threads of fabric, and blood samples.

All of this spelled trouble for J. Edgar Hoover. At the very moment he was launching a hemisphere-wide hunt for spies who communicated in code, his bureau had no ability to discover what they were saying.

Around this time, Elizebeth received an unusual order from her Treasury bosses: They asked her to visit FBI headquarters. She was to teach codebreaking to an agent named W. G. B. Blackburn, an employee in the Technical Lab. Elizebeth proceeded to train Blackburn in codes and ciphers, much as she had trained her own junior colleagues, and Blackburn established a small Cryptographic Branch at the FBI, which would grow to the size of a handful of employees over the next several years, all of them codebreaking novices.

This still wouldn’t do for Hoover’s purposes. The Invisible War demanded a level of technical firepower and prowess that his Technical Laboratory simply did not command. What he required was the full assistance of a mature codebreaking organization, whether they wished to help him or not. He needed Elizebeth and the coast guard.

She read pacifist poetry. It resonated. She thought of her kids. Barbara was in her last year of high school and planned to attend college at Radcliffe, and John Ramsay was a fourteen-year-old freshman at Mercersburg Academy, an elite boys’ school in rural Pennsylvania. He wasn’t young enough to be safe from a military draft. War would scatter her family. She also worried about the fate of her team at the coast guard. She had built this little organization and it was good and she wanted to protect it from disruption. Codebreaking is delicate work. You have to look at the page and get all the letters aligned just right, then you have to look at your team and get all the people aligned just right, so that the flow of intercepts and records and ideas and solutions becomes as efficient as possible.

Elizebeth escaped Washington for a week in June 1940, traveling to Mexico on a quick vacation with daughter Barbara and sister, Edna. It was the last time in the next five years she would get a break, a chance to pause and look around and spend time with the women closest to her. They drove a beat-up rental car through the farmlands of Oaxaca and the mountain ranges of Puebla Cordoba, descending into canyons on the backs of burros. Elizebeth wrote to William, “All Mexico is so full of resounding cockcrows, pig-grunts, burro-brays, and church bells that all sleep is intermittent, at best.” The two sisters had a great time and woke up early each day; Barbara wanted to sleep in and complained that the altitude made her knees wobbly. She was a gorgeous girl of seventeen now, six inches taller than her mother, confident and voluptuous. One day, when they were all on a plane above Oaxaca, Elizebeth happened to fall asleep in her seat, and when she woke, she saw Barbara up in the cockpit, next to the pilot. Wait, what kind of airline was this? Are girls just allowed to ride in the cockpit without their mother’s permission? Isn’t that unsafe? She felt like a mom.

The news of the war got rapidly worse while she was in Mexico. She had to stop reading the papers in the morning because it was too depressing. Nazi tanks were said to be plowing through the French countryside on the way to Paris. The Mexican papers seemed to think America was bound to join the war. The peso was rising, eating into Elizebeth’s meager trip budget of fifty dollars. She airmailed William a letter about the rising cost of goods. In his reply he begged her not to spend more money than was absolutely necessary, “or we shall never never climb out of this morass of debt.”

She wasn’t sure if William was okay. He sounded sad and mopey in his letters. He said it had been rainy in Washington, and in the evenings he had been sitting alone with a pencil and a pad, listening to the rain on the roof, writing a technical paper on cryptology. He told her, “There won’t be anybody [to] read this thing, I imagine, at least not for some centuries,” and added a lament about the shackles of secrecy: “I wish I could write about forbidden subjects. What a story could be told.”

By the time she got back to Washington—to home, husband, and job—the Nazis had entered Paris, hanging the swastika flag from the Arc de Triomphe.