Depression prevention therapies have had mixed results. Those that are implemented universally have shown little efficacy, although those that specifically target adolescents at risk of depression have shown greater efficacy. A large scale effectiveness trial—one that applies treatments outside of a lab in "real world" settings—of a targeted depression prevention therapy has not been conducted. This study will test the effectiveness of two therapies for preventing depression in adolescents. The first is a brief, group cognitive-behavioral depression prevention program, and the second is bibliotherapy, which involves giving participants a self-help book for depression. Bibliotherapy has shown efficacy in previous research but has not been examined in an effectiveness trial.