A provocative and original history of the scientists and writers, artists and philosophers who took drugs to explore the hidden regions of the mind A New Yorker Best of the Week Pick “Jay is a leading expert on the history of Western drug use, and Psychonauts is the latest in a series of excellent studies in which he has investigated the roots of a kind of psychoactive exploration that we tend to associate with the nineteen-fifties and sixties.”—Clare Bucknell, New Yorker “Captivating. . . . A welcome reconsideration of the role drugs play in life, medicine, and science.”—Publishers Weekly Until the twentieth century, scientists investigating the effects of drugs on the mind did so by experimenting on themselves. Vivid descriptions of drug experiences sparked insights across the mind sciences, pharmacology, medicine, and philosophy. Accounts in journals and literary fiction inspired a fascinated public to make their own experiments—in scientific demonstrations, on exotic travels, at literary salons, and in occult rituals. But after 1900 drugs were increasingly viewed as a social problem, and the long tradition of self-experimentation began to disappear. From Sigmund Freud’s experiments with cocaine to William James’s epiphany on nitrous oxide, Mike Jay brilliantly recovers a lost intellectual tradition of drug-taking that fed the birth of psychology, the discovery of the unconscious, and the emergence of modernism. Today, as we embrace novel cognitive enhancers and psychedelics, the experiments of the original psychonauts reveal the deep influence of mind-altering drugs on Western science, philosophy, and culture.