This talk will review research conducted at Johns Hopkins over the past two decades with psilocybin, a classic psychedelic substance which is the principal active component of the so-called "Magic Mushroom." Classic psychedelics are a class of psychoactive compounds that produce a unique profile of changes in thoughts, perceptions and emotions, often including profound alterations in meaning and beliefs about the nature of reality, that are rarely experienced except in naturally-occurring mystical experiences, and acute psychosis. A robust and provocative finding is that administration of psilocybin to carefully screened and well prepared and supported participants can result in "peak" experiences to which participants attribute enduring positive changes in moods, attitudes, beliefs, and behavior for months and possibly years after a single session. Notably, such effects have been documented in the majority of participants from a series of studies in healthy volunteers and in patient populations. This research has immediate applications in therapeutics and has broad implications for advancing our understanding of consciousness, prosocial and ethical behavior.