Public health and antiseptic measures, vaccination and antibiotics, have all contributed to the reduction in the incidence and impact of diseases due to infections in younger age groups. Unfortunately, however, infections remain a very important cause of both morbidity and mortality in the elderly. The reasons for the continued effect of infection on the older person are multifactorial. Firstly, the immune response alters with age and may result in opportunistic infections. Secondly, while the diagnosis and management of some infections in the elderly can present little problem, altered signs and symptoms in other older patients, especially the old elderly, can cause considerable diagnostic difficulties with resulting delays in definitive treat­ ment. Thirdly, a degree of complacency can develop because some infec­ tions are seldom seen and, consequently, may not be considered in the differential diagnosis. The presence of other, more common, diseases serve only to distract attention and confuse the diagnosis. Since the number of elderly people is increasing, the need for continued high standard of skill in diagnosis and management is emphasized. These factors are considered in this book by contributors who are experi­ enced in their fields. The altered immune response with age, the appropriate use of antibiotics in older people and the latest developments of therapy are reviewed. Infections in various body systems are considered, with emphasis on differing presentations and diagnostic difficulties, ways of improving diagnostic skills as well as management and treatment.