Book excerpt: A recent wave of research in psychiatry and neuroscience has re-examined the properties of “classic” psychedelic substances - also known as serotonergic hallucinogens - such as psilocybin, LSD, and DMT. Evidence to date suggests that psychedelics can be given safely in controlled conditions, at moderate to high doses, and may have potential as therapeutic agents in the treatment of various addictive and mood disorders. The main mechanism of action appears to be the induction of a dramatically altered state of consciousness, but the details of how psychedelic-assisted psychotherapy works are hotly debated, as are the relations between psychedelic experiences themselves and the neural changes induced by the drugs. Philosophical Perspectives on Psychedelic Psychiatry addresses the fascinating philosophical questions raised by the renewed psychiatric use of psychedelics, with chapters from leading philosophers of mind, science, and psychiatry centred around three main themes. Chapters in the “self and mind” section ask: what can we learn about the self and the mind from psychedelic science? Chapters in the “science and psychiatry” section address methodological, theoretical, and clinical questions concerning how psychedelics can best be studied scientifically and used therapeutically, and how they might work to relieve psychiatric suffering. Finally, chapters in the “ethics and spirituality” section address broader questions about the interpretation of psychedelic experience, its ethical implications, and its possible role(s) in the broader culture.