The Immortality Key: The Secret History of the Religion with No Name (2020) [ebook+audiobook]

The essential argument of the book is that many ancient Greek and Roman religious practices involved the ritual ingestion and use of psychedelic substances. These substances contributed to the life-altering religious experiences that ancient people report having at, for example, Eleusis in ancient Greece. The Eleusian Mysteries, based on myths about Demeter and Persephone, were the most famous secret religious rites in the ancient world. Initiates would drink kukeon, a beverage that had mind-altering capabilities that far outstripped those of alcohol. We know that some of antiquity’s most prominent thinkers—like Plato and Marcus Aurelius—visited Eleusis and were permanently transformed by what happened there. An inscription at the site states that “death is for mortals no longer an evil but a blessing” and the famous fifth century B.C. poet Pindar says that those who go there “understand the end of mortal life.” The mysteries were wildly popular and only ended when the Christian emperor Theodosius outlawed them in 392 A.D.