Author’s Note

Heinrich Himmler is, of course, a real historical figure, and the words he speaks in Chapter I are taken from the transcript of a speech he delivered in January 1937. Many of his other actions and words in this novel are my own invention. Other historical characters act more or less in keeping with the historical record including Alan Turing, Dilly Knox, Gordon Welchman, Mavis Batey, Heinz Kurschildgen, and Karl Malchus (the last two of whom really did try to convince Himmler that they had mastered alchemy). The workings of the Enigma machine and the breaking of the code using the Bombe, the checking machine, and some first-class deduction and mathematics have been simplified somewhat but are essentially the same in this novel as the heroic work conducted at Bletchley Park during World War II.