Due to the successful union between computational technologies and basic laws of physics and biological sciences, many biomedical imaging systems now find significant presence in clinical settings, aiding physicians in diagnosing most forms of human illness with more confidence. In the case of breast imaging, apart from the basic diagnosis, these imaging systems also help in locating the abnormal tissues for biopsy, identifying the exact margins of the lesion for good lumpectomy results, staging and restaging the cancer, detecting locations of metastases, and planning and following up treatment protocols. It is well known that early detection of cancer is the only way to increase the survival rate of the patient. Without such imaging systems, it would be hard and almost impossible for the physicians to determine the nature and extent of the disease by merely simple physical examinations and biopsies. This article presents a description of most of these invaluable breast-imaging systems. Moreover, a comparison of these modalities and a review of a few of the developments these devices have come across over the years are also given.