A brisk book about intelligence coups--chiefly Anglo-American--and the technological breakthroughs that facilitated them, by a novelist and accomplished writer. During WW II, Fitzgibbon served as the US 12th Army Group's intelligence officer in charge of receiving ""Ultra"" briefings from the secret British headquarters at Bletchley that deciphered German Enigma Machine radio dispatches between Hitler and the German high command. This too-good-to-be-true listening post, complains Fitzgibbon, made the Allies ""reliant on Ultra to a dangerous extent,"" but among Ultra's coups were the British warning to the US that the Alaska-bound Japanese navy was in fact heading toward Pearl Harbor, and that the Germans intended to launch the 1944 Ardennes offensive. Fitzgibbon also describes the Allies' active use of information and misinformation, feeding the latter to the Germans to ensure the success of the Normandy invasion, and providing the former to the Russians through an elaborate Swiss network because the British did not want to reveal their sources. The book describes British penetration of the Nazi Sicherheitsdienst-Abwehr intelligence group, whose Col. Oster gave the West intelligence, and which fabricated the documents leading to the execution of the brilliant Soviet tactician Tukachevsky. Though fiercely pro-British and anti-Communist, sometimes fluffy and sometimes elliptical, this is one of the most rewarding books in this genre, a broader companion to Winterbotham's The Ultra Secret (1975).