This book presents a precise description of a new method and technology for early diagnosis of breast cancer and cancer of the thyroid gland. The method employs mathematical/statistical techniques of pattern recognition and state of the art results in oncomorphology and cytometry to detect and identify malignancy-associated DNA changes in patient's buccal epithelium, which provide early signs of the disease before other symptoms, such as the formation of a tumour, become evident. The method is non-invasive and requiring a scrape of buccal epithelium from the patient's oral cavity for analysis. The results of recent clinical trials show that the sensitivity and specificity of the method compares favourably with other diagnostic methods currently in use. Conventional methods, such as mammography and ultrasound, are important tools in screening patients for cancer. However, their reliability is limited (see, for example, "Mammogram Team Learns from its Errors", New York Times, page 1, June 28, 2002). Thus the problem of improving the reliability of non-invasive methods for early diagnosis of cancer has been the subject of intense research in recent years. This book is the first of its kind on the topic of computer-aided cytogenetic method of cancer diagnosis and presents a new approach to this problem. The book is divided into four chapters and consists of approximately 300 pages and 40 figures. It is intended for graduate students, researchers and professionals in the field of oncology, medical diagnostics and cancer research.