Fluid mechanics continues to dominate the world of engineering. Applications only seem to be proliferating, and the importance of teaching the subject from first principles is widely felt. The second edition maintains this focus, while continuing to establish the link between principles and practice. The goal is to be train students so that they can create, design and analyze flow systems in the real world. This book was first published in 1996, and revised edition was released in 1999. Quite a few comments and suggestions have been received from students and colleagues. These ideas form the basis of the second edition. The book bridges the gap between first and higher level text books on the subject. It shows that the approximate approaches are essentially globally averaged versions of the local treatment, that in turn is covered in considerable detail in the second edition.