Although tamoxifen is one of the most widely prescribed drugs for the treatment of breast cancer, disturbing questions remain about its use. How effective is tamoxifen in treating patients who have not yet reached menopause? What are the potential risks in taking tamoxifen, and do they ever outweigh its benefits? Should tamoxifen be administered as a prophylactic drug for healthy premenopausal women who are at high risk of developing breast cancer? In this vitally important book, two leading scientific investigators present a balanced and accessible discussion of the diagnosis of breast cancer and the risks, benefits, and limitations of treatment alternatives, particularly tamoxifen.