This publication was written for therapists and their supervisors who may want to implement the adolescent community reinforcement approach intervention, which was one of the five interventions tested by the Center for Substance Abuse Treatment's (CSAT's) Cannabis Youth Treatment (CYT) Project. The CYT Project provided funding to support a study that tested the effectiveness of five interventions designed to reduce or eliminate marijuana use and associated problems in adolescents. Although information is still emerging about adolescent treatment effectiveness, there is considerable tension between efforts to develop short, cost-effective treatments and findings that 50 percent or more of adolescents relapse to marijuana or alcohol use within the first 3 months after discharge. There are, however, several promising options for improving treatment effectiveness that focus on motivational enhancement, relapse prevention, problem solving, coping strategies, case management, family support, family therapy, and working with adolescent' to change their environments. This manual guides therapists and their supervisors in using the adolescent community reinforcement approach (ACRA) intervention with adolescents and their caregivers. The guide provides examples of exchanges between therapists and adolescents to illustrate how therapists help adolescents find or enhance reinforcers to abstinence, use community resources to support change, and develop family support. An appendix includes a detailed account of the CYT study. (Contains 51 references.) (GCP)