This publication reviews a variety of empirically supported approaches to dealing with alcohol and drug problems in adolescents. Its focus is to provide motivationally based brief interventions that can be delivered in a variety of contexts address key developmental considerations and draw on the latest knowledge about the processes of addictive behavior change. Information was obtained from a multidisciplinary group of experts to create this resource guide for anyone working with or studying adolescents-at-risk. Part 1 reviews current research on substance abuse in adolescents and young adults and outlines the basic principles of developmentally informed assessment and intervention. Emphasized are the benefits of working with adolescents on their own territory and reaching out to all who are engaged in health-risk behavior. Part 2 presents a range of specific interventions, including skills training for substance abuse prevention; integrative behavioral and family therapy; motivational interviewing; interventions for dually diagnosed youth; Internet-based education; and applications to HIV prevention. The chapters describe the goals and methods of these approaches, review available data on treatment efficacy, and offer case studies along with clinical interpretations. Part 3 discusses future directions for brief interventions for addictive behaviors. (Contains over 500 references.) (JDM)