A diagnosis of cancer in adolescence occurs at a critical time of social and interpersonal development. Adolescents are encountering rapid physical growth, hormonal changes, and a shift from dependence on parents with associated reliance upon close peer and dating relationships. These close relationships often involve increased levels of intimacy and sexuality, and it is in the context of these relationships that adolescents are developing important competencies for later relationships in their adult years. A diagnosis of cancer in adolescence is likely to impact close relationships, although research in this area is scarce. We know little about how close relationships may impact critical aspects of adolescents' lives, such as quality of life, psychological distress, and health behaviors. The current study was designed to address these gaps in the literature by providing an examination of how dimensions of close peer and dating relationships correspond with ratings of quality of life, psychological distress, and health-related behaviors among a sample of adolescents currently on treatment for cancer. In this first critical study of close peer and dating relationships among adolescents on active treatment for cancer, Drs. Carpentier and Mullins examine specific, discrete dimensions of close relationships (i.e., social support, negative interactions, dating anxiety, fear of intimacy) that are thought to relate to quality of life, psychological distress, and health-related behaviors (i.e., tobacco, alcohol, and other drug use; sexual risk-taking; nutrition/physical activity; overweight and dietary behaviors; sun safety). Results of this study provide an understanding of the importance ofclose relationships to adolescents' adaptation to cancer and highlight the need for continued examination of discrete aspects of close relationships among this presumably vulnerable population. Adolescents with Cancer is an important book for collections in adolescent studies, pediatric cancer, and psychology.