features of the present book are a continuation and - velopment of the spirit and logical structure of a Chinese monograph by the same authors, Introduction to Vorticity and Vortex Dynamics, Higher VI Preface EducationPress,Beijing,1993,butthematerialhasbeencompletelyrewr- tenandupdated.Thebookmay?tvariousneedsof?uiddynamicsscientists, educators,engineers,aswellasappliedmathematicians.Itsselectedchapters canalsobeusedastextbookforgraduatestudentsandseniorundergraduates. Thereadershouldhaveknowledgeofundergraduate?uidmechanicsand/or aerodynamicscourses.