Fluid Mechanics in its ninth edition retains the informal and student-oriented writing style with an enhanced flavour of interactive lecture. Fluid Mechanics as a subject is as an important branch of engineering mechanics. The essence of the subject is a judicious compromise between theory and experiment. This textbook not only makes a great deal of theoretical treatment available, but also provides experimental results as a natural and easy complement to the theory. The principles considered in the book are fundamental and have been well established.