1.    This would appear to be Watson’s mysterious second marriage.

  2.    During the years of the Great Hiatus, Holmes claimed to have visited Lhasa, which the British captured in 1904.

  3.    Watson appears to have married the sister of the literary critic Edward Garnett, whose wife, Constance, was the first English translator of Tolstoy et al.

  4.    The Diogenes was the original headquarters of what became the British Secret Intelligence Service (SIS). The SIS was formalized as MI-6 in 1920 (the year the old club was razed) and its offices relocated near Piccadilly Circus. It was henceforth familiarly dubbed “the Circus” by those who toiled there.

  5.    This is as it appears in Watson’s original ms.

  6.    Holmes must have owned one of the first editions of this invaluable reference.

  7.    This refers to cricket, a game beyond the comprehension of Americans.

  8.    So far as I know, this is the only reference to Martha Hudson’s brother.

  9.    Lord Beaconsfield, aka Prime Minister Benjamin Disraeli. Queen Victoria liked to call him “Dizzy.”

  10.    In A Study in Scarlet, Watson characterizes Holmes’s knowledge of politics as “feeble.”

  11.    Six years earlier, during the Boer War, a then twenty-five-year-old Winston Churchill had made a daring prison break, whose successful outcome he had cleverly parlayed into a parliamentary career, while Watson, by contrast, badly wounded at the Battle of Maiwand during the Second Afghan War (1880), was invalided out of the service with a mere nine months’ soldier’s pension.

  12.    Cassel was to become the grandfather of Edwina Ashley, who, as Lady Mountbatten, was the last vicereine of the Raj and as such enjoyed a passionate love affair with India’s first Prime Minister, Jawaharlal Nehru.

  13.    In July 1904 in Edlach, a village in Reichenau an der Rax.

  14.    Things seem to have been a lot more casual back then regarding top-secret stuff. Or were they? Today government officials are always taking home restricted documents, using the wrong email server, or leaking like a sieve. Maybe it hasn’t changed at all.

  15.    For details of Brownlow Sr.’s disappearance, the reader is advised to consult an earlier Holmes case, “The West End Horror.”

  16.    Highgate Cemetery, also a nature preserve in North London, is, among other things, the final resting place of Karl Marx.

  17.    Turgenev visited Oxford in 1879.

  18.    Conrad? First name? Surname? Not clear.

  19.    These notes in the same hand I found on a different sheet of paper slid at this point between the pages of the diary. I’m not sure this is where Watson intended them to go, or even if he inserted them here, but I hesitate to move them elsewhere.

  20.    Louis Napoleon, an unscrupulous adventurer with luxurious tastes, was the self-styled nephew of Napoleon Bonaparte who in 1851 undertook a coup d’etat, proclaiming himself Napoleon III. Defeated by Prussia, he fell from power in 1870.

  21.    The mutiny appears to have been prompted by maggot-ridden rations.

  22.    Diathesis = a preexisting medical condition.

  23.    After the death in 1939 of one of the principals involved, Watson chronicled the case, which he labeled “The Seven-Per-Cent Solution.”

  24.    In 1949, Professor Chaim Weizmann became the first president of Israel.

  25.    Graustark, like Ruritania or Lilliput, is one of those fictitious countries where novelists are pleased to indulge all manner of over-the-top costumes and customs. Napoleon III and his court definitely fall into such comic-operetta territory.

  26.    The following year, 1906, Captain Alfred Dreyfus was formally exonerated and reinstated with full rank in the French army.

  27.    As the result of the slaughter and its ensuing notoriety, Kishinev changed its name to Chisinau.

  28.    Richard D’Oyly Carte, who built the Savoy Hotel and adjacent opera house of the same name.

  29.    In England, civilian surgeons are typically titled Mr., not Dr.

  30.    Mycroft was prescient. Holmes would eventually spend two years in America, working undercover for his brother in the run-up to World War I.

  31.    Those details may be found in the aforementioned “The West End Horror.”

  32.    That would be Irene Adler, referred to by Holmes as “the” woman in the case Watson dubbed “A Scandal in Bohemia.”

  33.    The book, published in 1908, was titled Russia’s Message.

  34.    Watson, I believe, is noting what he heard phonetically. I think Walling was referring to W. E. B. Du Bois, American civil rights activist and author.

  35.    The NAACP was founded in the New York apartment of William English Walling and his wife, Anna Strunsky, in 1909. W. E. B. Du Bois was among the founders.

  36.    Yasnaya Polyana today is a museum.

  37.    It was not until 1964 that the University of Glasgow developed a test of human hair to detect the presence of excess arsenic in the body, suggesting, among other possibilities, the poisoning of Napoleon on St. Helena.

  38.    The “business car” (car number 3557) was short-lived, being discontinued in 1908. The staff, originally male, was quickly changed to female typists, who appeared more amenable when summoned at odd hours.

  39.    The route of the fabled train varied over the years. Some versions later went to Constantinople, aka Istanbul, while others finished up in Athens.

  40.    Holy cow. Where are those missing pages??

  41.    An ecclesiastical title in the Greek Orthodox Church. A metropolitan typically ranks above an archbishop and below a patriarch.

  42.    Holmes’s violin was allegedly a Stradivarius. Watson, whose judgment in such matters is questionable, deemed the detective an accomplished player.

  43.    Consumption or tuberculosis.

  44.    In his 1925 epic, Battleship Potemkin, director Sergei Eisenstein staged the slaughter on the unending steps, one of the most famous sequences in all cinema.

  45.    Miss.

  46.    Watson accounted Holmes a master of this Japanese mode of self-defense, introduced in England in 1899 by E. W. Barton-Wright.

  47.    The French translation of the Protocols from the Russian has subsequently been attributed to one Mathieu Golovinsky, a hack propagandist living in Paris, in the pay of the Okhrana.

  48.    Carbon or “carbonic” paper was first invented around 1806, but its use was not fully popularized until the advent of the typewriter. Places such as rural Russia were unlikely to have any in 1905.

  49.    This sentence appears to have been added later.

  50.    Watson, the diarist, appears to have been unaware of this pun.

  51.    If the Russian is speaking truthfully, he attended the same university as Holmes. Though they appear roughly the same age, it would be too improbable to discover they were classmates.

  52.    Sergius Yulyevich Witte (1849–1915) became Russia’s prime minister in 1905 and designed Russia’s first constitution. He was loathed by the Okhrana.

  53.    The funicular opened in 1870 and was in continuous operation until bombed by the Allies in World War II. It was restored after the war and continues to function.

  54.    Women in England did not get the vote until 1918; in the United States they got it in 1920.