For close to 2000 years the Mystery was performed every year (except one) for carefully screened initiates in our month of September. Everyone speaking the Greek language was free to present himself, except only those who had the unexpiated blood of a murdered man on their hands. The initiates lived through the night in the telesterion of Eleusis, under the leadership of the two hierophantic families, the Eumolpids and the Kerykes, and they would come away all wonderstruck by what they had lived through: according to some, they were never the same as before. The testimony about that night of awe-inspiring experience is unanimous and Sophocles speaks for the initiates when he says: Thrice happy are those of mortals, who having seen those rites depart for Hades; for to them alone is granted to have a true life there. For the rest, all there is evil. Yet up to now no one has known what justifies utterances such as this, and there are many like it. Here lies for us the mystery of the Eleusinian Mysteries. To this mystery we three have applied ourselves and believe we have found the solution, close to 2000 years after the last performance of the rite and some 4000 years since the first. The first three chapters of this book were read by the respective authors as papers before the Second International Conference on Hallucinogenic Mushrooms held on the Olympic Peninsula, Washington, on Friday, 28 October 1977.