The papers focused on AIDS risk behaviors of heterosexual male drug users, including both injecting and noninjecting drug users; HIV risk behaviors among women who use drugs or who are sexual partners of injecting drug users; and HIV risks among homosexual and bisexual male drug users. Some papers focus on adolescent drug users, including adolescents attending schools and homosexual and bisexual adolescent males involved in a range of drug-using and sexual risk behaviors, including injecting drug use and male prostitution. Some papers examine measurement issues in research on HIV risk behaviors and present a multidimensional conceptual framework, a discussion of the role of qualitative research, and an analysis of issues of reliability and validity of self-reports of risk behaviors. Tables and chapter reference lists