Aleister Crowley is best today as a founding father of modern occultism. His wide, hypnotic eyes peer at us on the cover of The Beatles' Sergeant Pepper's Lonely Hearts Club Band, and his influence can be found everywhere in popular culture. "The Great Beast" has been the subject of several biographies, some painting him as a misunderstood genius, others as a manipulative charlatan. None of them have looked seriously at his career as an agent of British Intelligence. Using documents gleaned from British, American, French and Italian archives, Secret Agent 666 sensationally reveals that Crowley played a major role in the sinking of the Lusitania, a plot to overthrow the government of Spain, the thwarting of Irish and Indian nationalist conspiracies, and the 1941 flight of Rudolf Hess.