Immunology has become one of the most important of the life sciences. As research unravels the mystery of the lymphocyte, a central role of the immune system in health preservation has become evident. The paediatric immunodeficiency disorders or 'experiments of nature' have demonstrated the division of cellular and humoral immunity; specific functional defects are now readily identified. The tendency of persons with immune dysfunction to develop neoplasms has suggested that surveillance mechanisms within the immune apparatus prevent tumour development. Malignancies, in fact, do seem to provoke certain immune responses, begging numerous therapeutic questions. Transplantation surgery, or the demand for 'new parts' has led to description of those antigens important in tissue-typing. Genetic loci have been found responsible for transplantation antigen display; as well, they influence clinical resistance or susceptibility to a wide variety of infections, auto-immune or neoplastic diseases. Clinicians have been quick to recognize the therapeutic implications of laboratory work and to use this knowledge in disease treatment. Precise patient-tissue matching and immunosuppressive treatment make renal allo transplantation safer and more successful than ever before. Both paediatric and adult immune deficiency states are now often recognized; treatment may involve general immune support or specific manipulations with, perhaps, bone marrow or thymus grafts or treatment with lymphocyte transfer factor. Transplantation of bone marrow has been used not only to correct certain immune defects but to correct marrow failure of diverse origin."

Recent developments have favourably and extensively altered general surgical practice. As editor I have happily been able to select certain topics of new and major interest for detailed discussion and have thus had the opportunity to collect these authoritative submissions within the covers of one text. The range of topics is broad. Endoscopy has changed the nature of both investigation and treatment of much gastrointestinal disease and the therapeutic uses of endoscopy continue to grow. That sophisticated new tool of the radiologist, computerized axial tomography, has revolu tionized the diagnosis of intra-abdominal disease, very often permitting precise localization of hitherto occult disease, and, as might be expect ed, it has become helpful in determining both the nature and extent of surgical and other therapy. Although an invasive procedure, intra abdominal angiography has similarly come of age as a means of localiz ing gastrointestinal haemorrhage and controlling such bleeding. Unfortunately, intra-abdominal malignancy continues to be a major source of concern to the general surgeon and the discovery that such tumours are associated with unusual markers, termed oncofetal anti gens, suggests that early diagnosis and early detection of recurrence may yet be feasible. Adjuvant or post-surgical therapy is an exciting de velopment in terms of prolonging the disease-free interval in women with breast cancer limited to regional lymph nodes. Equally efficacious therapy is not yet available for patients with gastrointestinal cancer, highlighting the need for more specific drugs and drug combinations."