A common thread unites the eight books I’ve written. They all focus in some way on unsung heroes—individuals of courage and conscience who helped change their country and the world but who, for various reasons, have slipped into the shadows of history. Since seven of those books deal with war, specifically World War II, it’s perhaps not surprising that most of the heroes I’ve spotlighted have been men. Madame Fourcade’s Secret War is the exception.

I first became aware of Marie-Madeleine Fourcade while doing research on the French resistance for my most recent book, Last Hope Island. There were only scattered mentions of her in the books and journals I consulted at the time, but the little I learned about this elegant young mother of two—the only woman to lead a major French resistance network—made me want to know more. As I dug deeper into her story and that of Alliance, I discovered that both were far richer than I could have imagined. I found it hard to believe that she was so little known in the United States, and I decided to correct that deficiency.

My most important source was Fourcade’s own wartime memoir. Intensely human, it describes in minute detail the satisfaction and joy, as well as the fear and terror, of fighting back against France’s Nazi occupiers. An English translation, entitled Noah’s Ark, was published in the United States in 1974. The original French version, L’Arche de Noé, was published in 1968.

Also helpful were memoirs written by two of Fourcade’s top lieutenants—Jean Boutron (De Mers-el-Kébir à Londres 1940–1944) and Ferdinand Rodriguez (L’Escalier Sans Retour). Rodriguez’s memoir, which focuses on his hellish sojourn in Gestapo prisons, is one of the most chilling, moving, and heartbreaking books I have ever read about World War II.

I also learned much from a French biography of Fourcade by the historian Michèle Cointet and from the writings of the American historian Valerie Deacon about the wartime activities of Fourcade, Georges Loustaunau-Lacau, and others belonging to the French right.

My heartfelt gratitude goes to Fourcade’s daughter, Pénélope Fourcade-Fraissinet; Rodriguez’s son and daughter, Patrick Rodriguez-Redington and Elizabeth Pernet; and Charles-Helen des Isnards, the son of Helen des Isnards, another key figure in Alliance. Their generosity in sharing with me their memories and insights into their parents and other Alliance members, along with providing me with several previously unpublished accounts of the network’s activities, was of crucial importance in bringing these amazing individuals to life on the page.

Of the many noteworthy experiences I had while researching this book, the one that immediately comes to mind is a cocktail party hosted by Charles-Helen des Isnards and his wife, Sylvie, in their elegant Paris apartment. The other guests included Pénélope Fourcade-Fraissinet and her husband and des Isnards’s five siblings and their spouses, who had traveled from all over France to be there. The warmth of their welcome to me and my friend and colleague, Dorie Denbigh-Laurent, reflected their pride in their parents and their extraordinary achievements during the war.

And speaking of the wise and beautiful Dorie Denbigh-Laurent, I owe her a particular debt of gratitude—not only for helping me with translations but also for her expert guidance and counsel on all things French. I could not have done this book without her.

I’d also like to thank Tom Chapin, the son of Sylvia Bridou Chapin Smith (Marie-Madeleine’s onetime sister-in-law), who gave me access to his mother’s unpublished roman à clef novel about her experiences and those of Marie-Madeleine’s family during the war.

Thanks, too, to the historians whose work on the French resistance, Vichy France, and MI6 I learned from and drew on in writing Madame Fourcade’s Secret War and my other books about World War II. I’d like to single out M.R.D. Foot, Robert O. Paxton, Julian Jackson, Keith Jeffery, Simon Kitson, H. R. Kedward, Douglas Porch, Robert and Isabelle Tombs, and David Schoenbrun.

Also helpful were the French national archives (Archives Nationales de France) in Paris and the archives of the French ministry of defense (Service Historique de la Défense) in Vincennes, both of which have considerable material on Alliance and its members (much of it available online). Their records include an account of Léon Faye’s life and his written notes of his capture by the Gestapo, failed escape from 84 avenue Foch, and nightmarish imprisonment in Germany.

The Association of Friends of Alliance (Association Amicale Alliance), an organization of the network’s members and families founded by Fourcade after the war, also produced documents relating to Alliance’s history, including a lengthy—and poignant—report memorializing its agents who were killed by the Germans.

I want to thank Julie Summers, the author of several wonderful histories set in England during World War II, including Jambusters and Our Uninvited Guests, for her help on a number of matters, including putting me in touch with Florence Smith, a talented young British researcher and historian. Florence was kind enough to track down for me the unpublished memoirs of the British diplomat Patrick Reilly at the Bodleian Library in Oxford.

The outstanding collection of oral histories at the Imperial War Museum in London also proved to be extremely useful, particularly those of Hugh Verity and Barbara Bertram, who played major roles in the RAF’s wartime ferry service of Fourcade and other French intelligence agents between France and England.

Working on this book has been one of the most satisfying and enjoyable experiences of my writing life, in no small part because of the encouragement and guidance of my splendid editor, Susanna Porter, and the rest of the Random House team. I’ve also had the great good fortune to have the incomparable Gail Ross as my agent and friend—a relationship that has flourished for more than twenty years.

Above all, I must thank the loves of my life—my husband, Stan Cloud, and our daughter, Carly. You are my everything.