The Bletchley Park codebreakers who solved the Enigma Cipher and the Double Cross system that "turned" German secret agents helped cut the war by years and ensured the success of D-Day. Historian Michael Smith thrillingly recounts new details about these operations, with stories that range from extraordinarily courageous to bizarre, with desperation driving intelligence services to recruit astrologers and even a stage magician to help retrieve intelligence and aircrew.