The continuing success of the VICC's Manual of Clinical Oncology and the continuing refinement of our educational objectives in cancer designed for graduating medical students and young practitioners, cou pled with significant additional knowledge in the cancer field have allIed to the decision to publish a Fourth Edition. The collaboration of the World Health Organization (WHO) and the Pan-American Health Orga nization (PAHO) in our international and regional conferences in cancer education and the development of courses using the Manual as a basic resource have aided further definition of the VICC's role in cancer educa tion throughout the world. Our Revision Committee believes that we have incorporated in this small volume most of the knowledge about cancer which is essential for all students and practioners to know and that we have done so in a clear and concise manner. A large proportion of the material presented herein is devoted to basic aspects, yet presented so that the clinical implications are clear. Although we do not feel that general physicians need to know minor details about all cancers, we feel it is particularly important to be somewhat thorough in our discussions of the more common cancers. We have omitted discussion of the rare cancers, and limited ourselves to the major concepts and princi ples of the less common cancers.