To flesh out his search for the Holy Grail, the author joined the theories of classicist Carl Ruck and ethnomycologist Gordon Wasson with the research of both Roland Griffiths and Patrick McGovern, an expert in archaeological chemistry.

Trade publishers would have little interest in a 400-page goose chase for what intoxicants the oracles and prophets might have been smoking or sipping. (Ancient wines were frequently blended with botanicals, roots, fungi, and other potentially psychoactive ingredients.) And so The Immortality Key begins with a message for today.

Western civilization, Muraresku argues, is in the grip of a cata-clysmic "spiritual crisis" that can only be remedied through a "popular outbreak of mysticism," the result of retrieving the Eucharist's ancient, and until now secret, pharmacological roots.

And what are those roots? According to Muraresku, Christianity evolved from pagan mystery cults whose most sacred ritual involved the ingestion of a psychedelic fungus-and this sacrament, the kykeon, eventually became the Holy Eucharist.

A protégé of Graham Hancock (an Economist reporterturned conspiracy theorist who has made a fortune writing speculative bestsellers about purported lost civilizations), Muraresku told Vox that he has never taken psychedelics himself but eventually came to believe that the drugs can begin "a life of dedicated introspection, a path to love of self and others." His book claims that "about seventy-five percent would leave the FDA-approved house church permanently transformed. And ready to begin a lifelong spiritual journey that could, once again, make life livable on this planet. This should begin happening by 2030, if not sooner." Like the religious professionals' paper, The Immortality Key has been surrounded by controversy. Critics have already assailed it as a work of scholarship. Now many people depicted in the book are speaking out against it too.