This book is especially written for physicians and dentists who are new to the exciting field of lasers. It will give you a good reference for the physical and biophysical part of laser medicine and dentistry. It may also serve you well as a reference and study material in a fellowship or master's program. There are many books about lasers and laser physics, but these are written by physicists for physicists - and they generally do not address the specific knowledge a doctor needs to be aware of when it comes to laser-tissue-interaction. In this book, I want to cut to the chase. I will give you the background information you need when new to the field of laser medicine or laser dentistry: Your laser: what is that thing you just bought or are considering to use? How does absorption, scattering and transmission in biological tissues take place? On what parameters do the clinical effects depend? How can a laser be used as a minimally invasive tool in modern medicine?