This book is motivated by the very favorable reception given to the previous editions as well as by the considerable range of new developments in the laser ?eld since the publication of the third edition in 1989. These new developmentsinclude, among others, Quantum-Well and Multiple-Quantum Well lasers, diode-pumpedsolid-state lasers, new concepts for both stable and unstable resonators, femtosecond lasers, ultra-high-brightness lasers etc. The basic aim of the book has remained the same, namely to providea broad and uni?ed description of laser behavior at the simplest level which is...