The booklet defines the concept of early intervention, and describes components of early intervention programs implemented in school, community, juvenile justice, and health care settings. The study findings indicate that numerous early intervention programs are being implemented across the country, that few models have been evaluated, and that certain approaches, particularly student assistance programs, are being promoted without evidence of their effectiveness. The booklet emphasizes that the long-term effects of some early intervention programs, such as labeling adolescents or using adult therapeutic models for juveniles, need to be considered. 4 references