The volume provides a substantial contribution to the understanding of adolescent risk behavior, informative and useful for both scientists and practitioners. The chapters deal with each of the key risk behaviors that are of concern at this developmental stage: tobacco smoking, alcohol use, marijuana and other drugs use, precocious and unprotected sexual behavior, eating disorders, risky behavior, risky driving, deviant and antisocial behavior. The book combines theoretical analysis and the findings of a wide research project, where the multiple contexts in the ecology of daily adolescent life have been considered. The data are based on large normative samples and the presentation of findings is very accessible, relying throughout on graphic representation rather than statistical tables. The book describes the different risk behaviors, shows the linkages between them, and explains the functions served by the various risk behaviors or the meanings they may have for the adolescent. It examines how they vary with age, sex, and other demographic characteristics, and demonstrates the influential role the theoretical risk factors and protective factors play in adolescent risk behavior involvement. The research findings not only strengthen the theory, but serve as an important guide to the design of intervention efforts to prevent or reduce adolescent involvement in risk behavior. The authors emphasize the need to strengthen protective factors that can promote positive development, and the need to provide opportunities for behaviors that can serve the same purposes as risk behaviors do, but without compromising health and development. This is the key challenge for all western contemporary societies.