This book is an introduction to wind turbine aerodynamics for professionals and students with a diverse range of backgrounds. It is a self-contained textbook that shows how to progress from the basics of fluid mechanics to modern wind turbine blade design. It presents the fundamentals of fluid dynamics and inflow conditions, as well as extensive information on theories describing the aerodynamics of wind turbines. After examining a number of related experiments, the book applies the lessons learned to blade design. The text of this 3rd edition has been thoroughly revised, and the book includes a new section on aerodynamic design and optimization.