Mammography remains the major technique for detecting breast cancer. In Europe the screen-film technique is most frequently used, although the radiation dose in xeroradiography has been significantly reduced since liquid toner was introduced. The ultimate goal of mammography is to detect breast cancer at an early stage, especially through screening projects. The authors discuss the classic signs, such as calcifications and irregular shaped masses which are well known, and also the indirect signs. They insist on the necessity of having a special equipment to perform high quality views and focus on the importance of quality control.