The author of this monograph skillfully guides the reader, whether mathematician or physicist, through the background needed to understand and use the modern techniques developed...This book is a pleasure to read. It will be an excellent source, allowing the reader to build a proper intuition and of understand the basic facts of the theory...This book is also strongly recommended to researchers in Applied Mathematics who study various linear and nonlinear phenomena, but it may also be useful and comprehensive for a broader community od mathmaticians, physicists and engineers. I deeply believe that the present book is one of the most important works in its fieldthat have appeared until now...beautifully writtien and well organized, and I strongly recommend this book to anyone seeking a stylish, balanced, up-to-date survey of this central area of nonlinear partial differential equations.