Popov, a Yugoslav aristocrat, attended a German university in the late 1930's where he was recruited into the secret service, the Abwehr. The Nazis, though, were too heavy-handed and prudish for this bon vivant, and Popov decided to throw his lot with the British MI-5. After arranging a trip to England -- and a skillful assassination -- which satisfied both spymasters, he moved in espionage circles in Lisbon, London and America. He joined the Masterman doublecross organization, uncovered the German ""micropunkt"" document transmission system, and became the chief double agent ""Tricycle."" Popov informed the disbelieving J. Edgar Hoover of the impending Japanese attack on Pearl Harbor, and helped set up the Overlord Allied landing deception. The casual sexual episodes Popov relates are perhaps intended to back his claim that he was the prototype of James Bond. This memoir parallels Masterman's chronicle The DoubleCross System in the War of 1939-1945 (1972) but remains largely a fluid exercise in egoism and is probably a truth-and-fiction blend -- that was, after all, his profession. What Popov has done since the war is not mentioned, but he claims to have been released from MI-5.