This book reports a study of the medicalization of deviant behavior. The analysis focuses on the phenomenon of hyperactivity and the identification of hyperactive children. I use a sociology of deviance perspective in focusing on the definition, identification, and attribution of hyperactivity to children who exhibit deviant behavior. Central to this analysis is how deviant behavior becomes defined as a medical problem: this is analyzed in terms of the discovery of a medical disorder, the identification of children as hyperactive, and the medical diagnosis of hyperactivity. In short, this is a study in the labeling of hyperactive children as well as in the medicalization of deviant behavior.