Flashback: A middle-aged man enters a comfortably furnished room, sits on a couch and receives a pill. After swallowing the drug, his medical monitors place a mask over his eyes and headphones over his ears and encourage him to lie back. Soothing classical music plays, and during the next eight hours the self-identified religious man embarks on an inward journey occasioned by the drug: psilocybin, the active ingredient in magic mushrooms.

Thirty-six of these latter-day psychonauts participated in research designed to explore the pharmacological and psychological effects of psilocybin as compared with an active control--methylphenidate hydrochloride, commonly known as Ritalin. The double-blind study revealed that psilocybin produced a self-described mystical experience in 22 of the volunteers, and 24 of them rated it as among the most meaningful of their lives, comparing it with the birth of a first child or the death of a parent. In follow-ups, "they continue to report positive changes in attitude and behavior," says study leader Roland Griffiths of Johns Hopkins University. "And the experience continues to be personally and spiritually meaningful to them."