Non-ionising electromagnetic radiation - ultraviolet, visible, infrared, microwave, radio frequency and laser radiation - have exciting medical applications but are also potentially hazardous. Lasers are a late-twentieth-century phenomenon which present new opportunites in surgery as well as the potential for inflicting serious biological damage. By contrast, microwave and radiofrequency radiation have always been present but now the levels from man-made sources far exceed the natural background levels. Human exposure to ultraviolet radiation has also increased dramatically in recent years due to altered environmental status as well as changing recreational habits. This handbook describes the medical applications and health implications of such radiation, and emphasises the medical physics aspects of the subject, including safety in the hospital environment. The book concentrates on effects which are regarded as accepted given the current state of our knowledge, but discussion of more controversial ideas relating the 'electromagnetic pollution' is included for a complete picture. The Medical Physics Handbooks aim to provide up-to-date information on topics of interest on the field of medical physics. This volume will be useful to all medical and health physicists, health and safety officers in hospitals and industry, physicians and surgeons who use non-ionising radiation of one type or another, hospital administrators, and graduate physicists about to enter these fields.