This book offers a novel but unified treatment of an established subject. Rather than describe the standard topics in fluid mechanics in traditional form, the book presents each topic as part of a wider class of problems so that a unity of concepts is emphasized over a unity of material. The authors have aimed for simplicity in presentation, stressing physical understanding over mathematical development. Specialized subjects such as chaotic advection, chaos and the onset of turbulence - problems that are being tackled in research and industry now - are given particular attention. This text is intended for students of fluid mechanics, primarily at the graduate level, but will also be of interest and value to workers in the field of fluid mechanics.