In the past, the prototypes for characterizing drug use were heroin and cocaine, so that research has focused on possible commonalities between any substance and these drugs. Addiction controversies explores the problems of the commonalities approach by looking at dissimilarities as well. The first chapters of Addiction Controversies trace the development of modern medical attitudes to drug use and the current controversy over its decriminalization. The second set of chapters examines the extent to which drugs have common biological and sociological mechanisms of action and contrasts these explanations. The final chapters consider the extent to which the desires for different substances are the same and the biological and social explanations of relapse. Clinicians, researchers and students in all areas of substance use will be stimulated by these challenges to current thinking and will enjoy the comparative approach that is taken by the contributors to Addiction Controversies.