Operation Blunderhead was a unique SOE project to parachute an agent into occupied Estonia in 1942. The central character was an unlikely hero, and his survival owed more to his ability to spin a tale than to any daring qualities. Blunderhead was the only SOE operation in a country that had been incorporated into the Soviet Union in 1940, but it involved no cooperation with Moscow (although SOE sought permission for the go-ahead). Uniquely, the operation was not initiated by SOE, but was rather the brainchild of Ronald Sydney Seth (after the war he reinvented himself as Dr. Chartham, a pioneering sexologist). Seth left entertaining accounts of his training and these throw light on his extraordinary character and the ways in which SOE sought to prepare its agents. His mission was a failure: Seth was captured, interrogated by the Germans, and imprisoned. He claimed that he was saved from a public hanging by the failure to open at the last minute of the trapdoor on the scaffold. From Tallinn he was transferred to a succession of prisons in the Baltic and Germany and ended up in Paris with a mistress where he trained to be a German secret agent. In the war's final months he was taken to Berlin and entrusted with a mission to Britain sanctioned by Himmler. Was he a prisoner who agreed to work for the Germans, or was he a double agent?