Montagu, Garbo, Fuchs, Penkovsky... they were the greatest spies of the twentieth century. Through analysis of declassified documents, archives, reconstructions, and interviews, offers you a glimpse into the minds and methods of undercover operatives. Discover the tactics for transmitting top secret information. See how one man assumed 24 identities to simulate the existence of a spy ring. Witness how scientists provided the USSR with ultra-confidential plans for the atomic bomb.