Double cross

D-Day, June 6, 1944, was a stunning military accomplishment but it was also a masterpiece of trickery. Operation Fortitude, which protected and enabled the invasion, and the Double Cross system, which specialized in turning German spies into double agents, tricked the Nazis into believing that the Allies would attack at Calais and Norway rather than Normandy, thereby keeping the bulk of Hitler's army away from the actual invasion site. Now the story is told from the point of view of the five spies who formed the Double Cross nucleus. And there was a shadowy sixth spy, whose heroic sacrifice is revealed here for the first time.