In the 15 years of the acquired immunodeficiency syndrome (AIDS) pandemic much has been learnt about its natural history and complications. It is clear that the lung is a major target organ both for the human immunodeficiency virus (HIV), and a wide array of infectious and non-infectious pulmonary complications. A great deal of information on the epidemiology, microbiology, immunology, clinical features, diagnosis and management of these pulmonary complications has accumulated during the past 15 years. Given the enormous explosion in information, it is now timely to bring together this knowledge in this 25-chapter volume on AIDS and respiratory medicine. The contributors to this volume are prominent epidemiologists, doctors, microbiologists and scientists from Europe, USA and Africa. Professors Chretien and Enarson give a masterful account of the epidemiology of lung complications of HIV. Drs Zumla, Rowland Jones and Professor McMichael give a detailed summary of the lung immune responses to HIV. They outline normal lung defenses and discuss the consequences of HIV infection on them. The pulmonary radiological features of HIV and its complications as seen in the USA and Europe are illustrated by Professors Armstrong and Dee and this is compared and contrasted by Professor Tshibwabwa-Tumba who brings together his vast experience of chest X-rays in AIDS patients from Central Africa. Drs O'Doherty and Miller deal with the uses, and potential applications, of nuclear medicine in imaging of the chest in AIDS patients.