This book is devoted to one of the most interesting and rapidly developing areas of modern nonlinear physics and mathematics – theoretical, analytical and numerical, study of the structure and dynamics of one-dimensional as well as two- and three-dimensional solitons and nonlinear wave packets described by the Korteweg–de Vries (KdV), Kadomtsev–Petviashvili (KP), nonlinear Schr¨odinger (NLS) and derivative nonlinear Schr¨odinger (DNLS) classes of equations. Special attention is paid to generalizations (relevant to various complex physical media) of these equations, accounting for higher-order dispersion corrections, influence of dissipation, instabilities, and stochastic fluctuations of the wave fields