Lasers were developed out of Einstein's theories, but the first work ing device was not produced until 1960. Since then, they have found applications in many areas of medicine, and hold promise for many more. This book has been written to provide a basic found ation on lasers - what they are, how they work, and what they can do for the patient. It assumes only a basic scientific background in the reader, and has many simple and clear diagrams. It should be of interest to clinicians, surgeons, nurses, safety officers, patients and interested laymen. The book consists of six chapters, and following a glossary of technical terms, begins with a brief discussion of the physics behind laser action. This section is illustrated with clear diagrams, and is written in an easy-to-follow style. It describes how laser light originates, and how it differs fundamentally from ordinary light. The remainder of the book is concerned with the use of lasers in medicine. Chapter 2 deals with the various ways in which a laser beam can interact with tissue, and shows how this depends on the particular laser being used. The following chapter describes some properties of those lasers which are most usually used in current medical practice, but also discusses new and experimental develop ments. There are various methods of getting the laser beam to the target tissue, and these are described in Chapter 4.