This book provides a scientific explanation of drug abuse and addiction for the general public. It clarifies the meaning of concepts such as intoxication, physical dependence, and addiction, and describes the changes in the brain that underlie these states. Indeed, this volume is unique because it presents a comprehensive picture of what actually happens to people and their brains when they chronically self-administer opiates, stimulants or alcohol. Complex mechanisms of drug action in the brain are made simple and comprehensible to the layman through use of informative analogies and salient graphics. Accounts of the effects of drug use and abuse on normal people create meaningful, easy-to-relate-to examples from everyday life.