"Intoxication: The Universal Drive for Mind-Altering Substances" is a scientific and cultural exploration of the pursuit of altered states of consciousness in both humans and animals. History 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.