Book excerpt: How historical, social, and cultural forces shaped the psychedelic experience in midcentury America, from CIA experiments with LSD to Timothy Leary's Harvard Psilocybin Project. Are psychedelics invaluable therapeutic medicines, or dangerously unpredictable drugs that precipitate psychosis? Tools for spiritual communion or cognitive enhancers that spark innovation? Activators for one's private muse or part of a political movement? In the 1950s and 1960s, researchers studied psychedelics in all these incarnations, often arriving at contradictory results. In American Trip, Ido Hartogsohn examines how the psychedelic experience in midcentury America was shaped by historical, social, and cultural forces--by set (the mindset of the user) and setting (the environments in which the experience takes place).