The communities considered include intravenous drug abusers who are black, Puerto Rican, and members of other Hispanic groups; white males; homosexuals; users of nonopiate drugs; and prostitutes. The analyses also consider several institutional settings, including school, drug abuse treatment facilities, the criminal justice system, shelters for the homeless, the social service system, and the health care system. The discussions emphasize the need for prevention programs for these populations and settings to go beyond just providing facts and to include strategies for behavioral change that encourage not only the initiation of risk reduction but also the maintenance of these behaviors. They also note the need for community prevention approaches that use multiple sources to encourage, support, and reinforce change; that are delivered by individuals and organizations with credibility and trust in the target community; and that incorporate social support within the community to reinforce behavioral change. Tables, figures, reference lists, and list of other research monographs from the National Institute on Drug Abuse.