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. Key updates have been made throughout the ninth edition, including: 1. Enhanced focus on readability to help students grasp and relate topics throughout 2. Updated examples and data to bridge the gap between conceptual contents and applications 3. Student-informed data which helped determine contents needing to be revised in order to enhance student comprehension and clarity, particularly for Chapters 2 to 7 where the backbone of fluid mechanics is laid out 4. Updated art and photos that either reflect the changes in devices in recent years or enhance the quality of the illustration 5. 1681 problem exercises sorted according to topic