In The Psychedelic Sacrament religious historian Dan Merkur reveals the secret teachings from the Judeo-Christian traditions that promote the use of psychedelic substances to enhance religious transcendence. Merkur elucidates a body of Jewish and Christian writings especially devoted to this tradition of visionary mysticism. He discusses the specific teachings of Philo of Alexandria, Rabbi Moses Maimonides, and St. Bernard of Clairvaux that refer to special meditations designed to be performed while partaking of teh "psychedelic sacrament." These meditations combine the revelatory power of psychedelics with the rational exercise of the mind, enabling the seeker to achieve a qualitatively enhanced state of religious transcendence.

In his earlier work The Mystery of Manna, a companion to The Psychedelic Sacrament, Merkur provided compelling evidence that the miraculous bread that God fed the Israelites in the wilderness was psychedelic, made from bread containing ergot--the psychoactive fungus that contains the same chemicals from which LSD is made. Many religious authorities over the centuries have secretly known the identity and experience of manna and have left a rich record of their involvement with this sacred substance. Building on this earlier research, The Psychedelic Sacrament sheds new light on the use of psychedelics in the Western mystery tradition and deepends our understanding of teh human desire for divine union.