This book is one of the major courses for specialty of hydropower engineering. Hydropower is the most important renewable and green energy, with great development prospects in the developing countries. It contains 4 parts with 13 chapters, in which the basic concepts, basic theories, design principles, and analysis methods on turbines, water conveyance system, hydraulic transients, and powerhouses are elaborated by incorporating many practical examples. This book can be used not only as the textbook for undergraduates in relevant specialties, but also as a reference book for engineers in design institutions.