Seizing the Enigma: The Race to Break the German U-boat Codes, 1933-1945, Revised Edition
David Kahn holds a PhD in history from Oxford University. He worked for thirty years as a journalist in New York and Paris, and taught intelligence courses at Yale and Columbia. In 2002, he was scholar-in-residence at the National Security Agency in Washington, D.C. His massive history of cryptology, THE CODEBREAKERS, is still considered the standard work on the subject.