This work is a social history of the devil. The figure of Satan has been a standing puzzle in the history of religion. This study examines his origins and his shifting functions. Satan is not present in classical Jewish sources (and scarcely present in traditional Judaism to this day). Images of Satan began to develop and proliferate in later Jewish sources not included in the Hebrew Bible. The book explores this early history or invention of the devil, and traces Satan's subsequent transformations as one of society's most necessary fictions.