This book examines methamphetamines, which have risen to the top of the American drug-policy agenda. For most of its history, it was regarded in law and public opinion as a secondary or regional concern, different from and less damaging than the drugs -- heroin, cocaine, and marijuana -- that have defined the focus of national drug policy. More recently, however, as the production, trafficking, and use of methamphetamine have spread, a gathering consensus has come to regard it as one of the most dangerous substances available in illegal markets.