Cancer is a chronic life-threatening disease that requires a comprehensive approach, including health promotion, prevention, treatment, rehabilitation, and palliation. Because primary care physicians are critically important to the implementation of cancer control strategies, we have devoted two issues of Primary Care to keeping primary care physicians informed about the most recent developments in cancer treatment and prevention. Part I focuses on identifying cancer risk factors and on screening and prevention for specific cancers such as breast, cervical, colon, and prostate cancer.