On June 21, 1941, Alfred Liskov, a German soldier stationed on the Russo-German border, defected to the Soviet army to reveal that the German invasion of Russia was due within a few hours. A startled Moscow sent a midnight alert to its border troops, but it was too late. Operation BARBAROSSA had begun. Thus began one of the greatest military surprises in history. Not only was Stalin completely duped, but so were all the world's intelligence services. Until now, experts and historians alike have remained mistaken as to who was fooled and how. Herein, Whaley unravels the BARBAROSSA mystery . This is a case study of the decisive role of secret intelligence, code breaking, and counter-espionage at one of the turning points of history. Whaley's solution will cause scholars to reexamine the role and causes of surprise in world affairs and will please any mystery fan.