This K07 Career Development Award application is designed to expand Dr. Dennis career development from cancer etiology to cancer prevention and control. The career development plan rests on mentoring directed by experts in cancer prevention research and protected time to foster my professional development as an independent cancer control researcher. A unique population, the Agricultural Health Study (AHS) cohort, will be used to examine sun exposure, sun protection behavior, and factors affecting these behaviors regarding the risk of melanoma in private pesticide applicators (farmers) and their spouses.