This is an examination of free water hydraulics. The topics covered in this book range from hydrostatic force calculations to the refraction, reflection and diffraction of oscillatory water waves. The author draws a careful distinction between kinematic and dynamic motions - the latter is treated in detail by the method of characteristics, which is regarded as one of the most rigorous approaches to unsteady flow. A special feature is the final chapter in which the author turns to the disruption of free surfaces by air and bubble motion, particularly in pipes.