A scientific and cultural exploration of the pursuit of altered states of consciousness in both humans and animals• Contains myriad studies and examples from the author's 20 years of research• By the foremost authority on the social and psychological effects of drug useHistory shows that people have always used intoxicants. In every age, in every part of the world, people have pursued intoxication with plants, alcohol, and other mind-altering substances. In fact, this behavior has so much force and persistence that it functions much like our drives for food, sleep, and sex. This "fourth drive," says psychopharmacologist Ronald K. Siegel, is a natural part of our biology, creating the irrepressible demand for intoxicating substances.In Intoxication Siegel draws upon his 20 years of groundbreaking research to provide countless examples of the intoxication urge in humans, animals, and even insects. The detailed observations of his so-called psychonauts--study participants trained to explicitly describe their drug experiences--as well as numerous studies with animals have helped him to identify the behavior patterns induced by different intoxicants. Presenting his conclusions on the biological as well as cultural reasons for the pursuit of intoxication and showing that personality and guidance often define the outcome of a drug experience, Siegel offers a broad understanding of the intoxication phenomenon as well as recommendations for curbing the negative aspects of drug use in Western culture by designing safe intoxicants.