The introduction and the opening chapter note that many episodes of "drug epidemics" have occurred in the history of the United States and that the actions that characterize the emergence of each new illicit substance and the social and legal responses that follow are part of a natural and recurring process. Thus, the responses to crack have suggested that crack posed dangers unseen in previous drug phenomena. In addition, policies have been based on media and political perceptions regarding crack rather than on empirical evidence from the social and behavioral sciences. Further articles examine the relationship between crack and violence, the nature of crack use and trafficking, and the sexual behaviors of young females in neighborhoods in which crack is concentrated. Tables, figures, chapter reference lists, and index to Volume 16 of the journal.