This book really began when I met Mavis Batey (née Lever) in 1997. At the time I had no idea that she had been a key figure in the breaking of the Enigma Code. On one occasion I got her to talk a little about her experience working at Bletchley, but it wasn’t until after her death that I discovered just how intimately involved she had been in the codebreaking. I thank Mavis for her friendship and her heroism. I had another acquaintance who worked at Bletchley—the mother of my dear friend Chris Stockwell. Betty Stockwell (née Swan) worked at Bletchley (and other locales) as a technician for the Bombe and other equipment. I didn’t know this about Betty until after her death, and this is one of the remarkable things about the thousands who worked at Bletchley—they did work that was as important, if not more important, as any done in the war, then quietly returned to their lives where they didn’t breathe a word about Bletchley for decades.

Mark and Catherine Richards organized the first trip that my wife, Janice, and I made to Bletchley Park—before it had been saved from ruin by lottery money and turned into a proper museum. We have been back twice and highly recommend it to anyone interested in World War II, computers, codebreaking, or this novel. Watching the reconstructed Bombe Phoenix at work is a remarkable experience.

Janice has a passion for Bletchley and the work that went on there which has inspired my own interest. She also listened patiently as I read this novel aloud on our back porch during the early days of COVID. Janice’s suggestions, both large and small, led to many improvements in the manuscript.

Anna Worrall is a patient, wise, encouraging agent who helped shape the manuscript, always pushing me in fruitful directions. Madeline Hopkins provided thoughtful and careful editing that eliminated many inconsistencies in a complicated story. And to all the rest of the staff at both the Gernert Company and Blackstone Publishing, I am grateful for their faith in me and their commitment to the world of books and reading. It is a commitment they share with another group to whom I am indebted—the booksellers of the world (and particularly those at Bookmarks in Winston-Salem), who have dedicated their lives to keeping reading alive.

I thank my children, Jordan and Jimmy, and their wisely chosen spouses, Jim and Conor, for more than can possibly be expressed here, but especially for their unwavering support and enthusiasm for my work.