Before landing in France on D-Day, June 6, 1944, the Allies executed an elaborate deception plan designed to prevent the Germans from concentrating forces in Normandy. The lesser-known first part, Fortitude North, suggested a threat to Norway. Fortitude South--largely through a fictitious army group under Gen. George S. Patton--indicated that Allied forces would come ashore in the Pas de Calais rather than Normandy. Barbier sheds new light on this story of double agents and phantom units while reassessing the importance of Operation Fortitude.