This monograph is the first major update of adolescent smoking behavior since the groundbreaking reports of the Surgeon General and the Institute of Medicine in 1994. The authors of this National Cancer Institute (NCI) Monograph report some progress toward reducing tobacco use among adolescents but also highlight areas in which more efforts need to be made. Several chapters examine trends in adolescent smoking behavior, among all adolescents nationally, different racial/ethnic groups, and among adolescents residing in specific States. Other chapters examine these trends using different national surveys as data sources and different analytical methods. Finally, the remaining chapters present data on macro-level policies and factors that influence the initiation and maintenance of smoking behavior among adolescents. While this Monograph documents some successes in the reduction of youth smoking initiation in some States and localities, there remains a need for an ongoing and exhaustive search for solutions, followed by committed and successful application to enable the country to reach its goals in the area of adolescent smoking.