An important underlying theme throughout this volume is diversity. As many of the articles stress, there is wide variation in adolescent behaviors, including problem behaviors, in regard to gender, race, ethnicity, and religiosity. This variation is evident in problem behaviors ranging from internalizing behaviors such as depression, with adolescent girls being much more likely to experience depression than boys; to externalizing behaviors such as precocious sexual activity and pregnancy, with African-Americans adolescents being at a significantly greater risk for experiencing these problems in comparison to adolescents from other racial groups.

The articles in this volume also illustrate the point that during adolescence, problem behaviors tend to co-occur. For example, adolescent substance abusers tend to exhibitadditional problem behaviors such as early sexual activity, delinquency, and depression. Therefore, consistent with recent empirical work, these articles advocate the study of the "whole" adolescent; in contrast to the examination of isolated behaviors.

The underlying ideas presented in this volume have important implications for prevention and intervention. Taken together, they suggest that prevention and intervention programs targeting adolescent problem behaviors should be comprehensive. Such programs need to address the entire system -- the interaction of the "whole" adolescent with his/her context. In addition, these articles suggest that prevention and intervention programs need to encompass variations in behaviors across adolescents, contexts, and time.