Thisbookisdesignedtointroducesomeimportantmethodsfornonlinearevolutionequations.、Nonlinearevolutionequations,i.e.,partialdifferentialequationswithtimetasoneoftheindependentvariables,arisenotonlyfrommanyfieldsofmathematics,butalsofromotherbranchesofsciencesuchasphysics,mechanicsandm