In this episode of the Making Sense podcast, Sam Harris speaks with Roland Griffiths about the current state of research on psychedelics. They discuss the historical prohibition against their use; the clinical and scientific promise of psilocybin, mescaline, LSD, DMT, MDMA, and other compounds; the risks associated with these drugs; the role of “set and setting”; the differences between psychedelics and drugs of abuse; MDMA and neurotoxicity; experiences of unity, sacredness, love, and truth; the long-term consequences of psychedelic experiences; synthetic vs natural drugs; the prospects of devising new psychedelics; microdosing; research on psilocybin and long-term meditators; the experience of encountering other apparent beings; psilocybin treatment of addiction; and other topics. In his Afterword, Sam discusses his experience on a large dose of psilocybin—his first psychedelic experience in 25 years. Roland Griffiths, Ph.D., is a Professor in the Departments of Psychiatry and Neurosciences at the Johns Hopkins University School of Medicine, and founding Director of the Johns Hopkins Center on Psychedelic and Consciousness Research. He is author of over 380 journal articles and book chapters, and has trained more than 50 postdoctoral research fellows. Roland has been a consultant to the National Institutes of Health, to numerous pharmaceutical companies in the development of new psychotropic drugs, and as a member of the Expert Advisory Panel on Drug Dependence for the World Health Organization.