Few if any diseases are specific to old age. However, factors such as multiple pathology and impaired feedback control mechanisms lead to non-specific or 'atypical' presentation of disease, to difficulties in diagnosis, to rapid deterioration of untreated disease and to a high incidence of complications. The geriatrician must include rehabilitation in clinical care plans, and also be aware of the cultural gap that may exist between the old and the younger members of a changing society. Ethical issues may arise in the distribution of scarce societal resources between different age groups, and in considering the needs and rights of caring relatives as well as those of the disabled older patient. Based on these considerations, this new textbook is designed to supplement rather than substitute for textbooks of general medicine. As a frame of reference it is specifically designed as a companion volume to the Oxford Textbook of Medicine. It draws on an international authorship with an emphasis on combining the fruits of experience in clinical geriatrics with a scientific base in research. The various chapters therefore offer both scholarly reviews of fields of knowledge in medical gerontology and firmly practical advice on clinical problems. Field reviews include biological origins and mechanisms of aging, age-associated changes in immunology and other host defences, injury responses, temperature homeostasis, memory, and the aging eye. Practical issues include the management of foot problems, back pain, and infections in older patients. Further chapters deal with ethical issues, the difficulties of carers, and the design of services. The book includes traditional concerns of geriatric medicine such as hypothermia and postural hypotension but also takes a wider perspective on aging with chapters on topics including the post-menopausal state and aging in the Third World. References have been kept to a moderate number aimed at providing a rational and selective entree to the literature rather thatn a comprehensive bibliography.