The introduction of lasers into operative medicine and advances in fiberoptic technology have made a significant contribution to minimally invasive surgery. This book was written to raise awareness of the capabilities and advant­ ages of lasers in urological surgery and to make this tech­ nology more widely accessible. The book reflects the cumulative experience of 25 years of laser research and clinical application, starting in 1972 with studies on laser­ tissue interactions, endoscopic studies with fiberoptic "sutures;' and the first clinical use of lasers in 1975 and 1976. These early efforts were followed by the develop­ ment oflaser lithotripsy in the early 1980 s and a Lubeck­ based research program leading to the development of a "smart" laser lithotriptor (Lithognost) in the late 1980s. There have been recent advances in the field of photo­ dynamic diagnosis based on the use of locally adminis­ tered photo sensitizers, a development that will redefine the role of the Nd:YAG laser in the treatment of bladder cancer. Perhaps the most interesting concept is the inter­ stitiallaser therapy of prostatic hyperplasia and, perhaps one day, certain forms of prostatic cancer. We have also developed a technique, first described in 1986, for the laser treatment of schistosomal bladder lesions. I dedicate this book to the many pioneers oflaser medi­ cine and to all the colleagues and research assistants who accompanied me on this journey. I cannot name them all; their names can be found in more than 300 publications.