Editor Jacob Needleman contends in this book that esoteric spirituality appeals to modern men and women because of its respect for the natural world, its nods to the scientific temperament, its psychological insights, and its emphasis on the sacralization of the profane. This encyclopedic work begins with an impressive survey of the ancient and medieval roots of esotericism in Hellenistic, Jewish, Christian, and Arab sources. The rest of the volume offers insightful and substantive selections on alchemy, astrology, theosophy, Rudolf Steiner and anthroposophy, Gurdjieff and his school, occultism, and other spiritual currents.