Mammography is a topic that, as a breast surgeon, I can't get away from. It's a useful tool that those of us who treat breast cancer patients have used for over 30 years to detect breast cancer in asymptomatic women and thus (or so we hope) decrease their risk of dying of breast cancer through early intervention. We have always known, however, that mammography is an imperfect tool. Oddly enough, its imperfections come from two different directions.