This presentation will summarize past and ongoing studies from the Johns Hopkins Psilocybin Research Project, which started about 15 years ago. Laboratory research includes administering psilocybin to healthy volunteers, beginning and long-term meditators, ordained clergy, psychologically distressed cancer patients, and cigarette smokers seeking abstinence. The results from several studies suggest that mystical-type experiences appear to mediate sustained positive changes in attitudes, moods, and behavior.