With increased effectiveness of medical treatment for cancer, greater attention has been directed to the quality of life of cancer patients and cancer survivors. Work on this topic is aimed at better understanding the determinants of quality of life and creating ways to optimize these outcomes. Insights from many disciplines inform this effort. For example, personality psychology suggests bases for naturally occurring differences in resilience but also suggests ways to enhance adaptation and promote greater resilience. The author's current work relies on a view of individuals as goal-seeking beings whose efforts toward desired outcomes are threatened by diagnosis and treatment of cancer. Some react to such adversity with increased efforts, others with a giving-up response. This difference promotes differences in emotional well being. The author's group is focused on enhancing adaptation and providing patients with skills for stress management that permit patients to remain engaged in the pursuits that form their lives. This stress-management intervention has reduced the prevalence of depression among breast cancer patients and has increased the extent to which they report positive sequelae from cancer. The latter effect also has been related to differential reduction in cortisol. Ongoing work is examining well being in longer term survivors, including the effects of this intervention and the possibility that the intervention will have positive consequences for physical health. Cancer 2005. © 2005 American Cancer Society.