This second edition, appearing about twenty years after the discovery of the laser is a substantially revised version of the first edition. It is, like the first, aimed at both classroom teaching and self-study by technical personnel interested in learning the principles of laser operation. In preparing the second edition the hope has been that both these aims will be better served as a result of the various improvements made. The main changes have been made with the following aims in mind: (i) To update the book. Thus new topics have been added (in particular on various new types of lasers, e. g. , rare-gas-halide excimer lasers, color-center lasers, and free-electron lasers), while on the other hand some topics have been given less emphasis (again this applies particularly to some types of lasers, e. g. , the ruby laser). Updating is especially important in the area of laser applications, and the chapter on this topic has therefore been com pletely rewritten. (ii) To make some improvements to the logical consis tency of the book by rearranging material and adding new material. Thus a few topics have been moved from one section to another and a new chapter entitled Laser Beam Transformation has been added. (iii) To further reduce the mathematical content, placing greater emphasis on physical descrip tions of phenomena.weiterlesen