Crowley, M. (2019). Secret drugs of Buddhism: Psychedelic sacraments and the origins of the Vajrayana. Santa Fe: Synergetic Press. Crowley uses his personal engagement with Buddhism and a review and analysis of ancient texts as a basis to address evidence for entheogenic substances in Tibetan Buddhism. Crowley provides a wide-ranging analysis of an idea that has gained increasing popularity—and controversy—that ancient Buddhist practices involved the use of entheogens. Crowley provides analyses of myth and ritual practices that reveal information regarding the identities of entheogenic sacraments of Buddhism and Hinduism.