The Church of Scientology remains one of the most controversial and poorly understood new religious movements to emerge in the last century. And among the most controversial questions in the early history of the Church is L. Ron Hubbard's involvement in the ritual magic of Aleister Crowley and the possible role of occultism in the development of Scientology. While some critics argue that Crowley's magic lies at the very heart of Scientology, most scholars have dismissed any connection between the Church and occultism. This article examines all of the available historical material, ranging from Hubbard's personal writings, to correspondence between Crowley and his American students, to the first Scientology lectures of the 1950s. Crowley's occult ideas, I argue, do in fact represent one—but only one—element in the rich, eclectic bricolage that became the early Church of Scientology; but these occult elements are also mixed together with themes drawn from Eastern religions, science fiction, pop psychology, and Hubbard's own fertile imagination.