Mammography is presented for the primarily nonradiologic audience. A brief historical review calls attention to some of the milestones in mammography and how it has changed. Xerororadiography is discussed, as it is one of the newer developments and is rapidly gaining broad acceptance in the United States. Clinical applications are included, with a discussion of the various entities which the radiologist can identify on the mammogram. Although the mammographic examination can be extremely accurate in the hands of interested examiners, some carcinomas will not be identified; of these, some can be discovered by routine physical examination. If mammography is made to stand alone, without a physical examination, some women with breast cancer will not be identified and will not receive prompt, adequate treatment. Mammography is an adjunct and a complement to the physical examination. Breast cancer screening appears to be effective in finding small, nonpalpable tumors, many very early in their growth. Definite evidence is now available that early diagnosis of breast cancer leads to prolonged survival. There is promise of further developments in the field of mammography.