This class offers an overview of the history, pharmacology, cultural uses and changing attitudes about psychedelic and other psychoactive substances around the world. After introducing the field of ethnobotany and its role in drug 'discovery' the course surveys shamanism from various perspectives: transcultural psychiatry, altered states of consciousness, New Age spirituality and the science of 'plant intelligence.' Readings investigate the legal and scientific repercussions of the 'psychedelic revolution,' while providing a critical assessment of questions around criminalization, commodification and appropriations of Indigenous knowledge.