This book argues that the religious visions and experiences of many religious founders were the result of mental health disorders or neurological conditions, thereby calling into question supernatural origins about the faiths that they developed. It constructs this argument by extensively utilizing psychiatric and other mental health and medical material that social scientists and religious studies scholars have underutilized in their analyses of religious experiences. Using a multi-disciplinary approach to examine psychobiographies of numerous major and minor religious figures in Judaism, Christianity, and Islam (Ezekiel, Sabbatai Sevi, St. Paul, John Wesley, and Muhammad), along with leaders of many newer or alternative sects and cults (Rajneesh, Charles Manson, L. Ron Hubbard, David Berg, Marshall Applewhite, Jim Jones, Sun Myung Moon, and Elizabeth Clare Prophet). The book integrates material from religious studies, psychiatry and psychology, neurology, and the social sciences to address issues related to religions’ origins. Its extensive bibliography makes it an indispensable resource for scholars of psychiatry and religion, new religious movements, and religious narcissism.