Based on the author's rich teaching experience, this textbook is an accumulated effort to systematically and comprehensively introduce the fundamentals of hydrodynamics and hydraulic transmission. This textbook is roughly divided into hydrodynamics (20%) and hydraulic transmission (80%).This is an English-language textbook for international students and undergraduates in Mechanical Engi- neering, with the 38 recommended teaching hours. The accompanying CD-ROM is a multimedia CAI courseware carefully made to assist teaching.