Classical wave theory pervades much of classical and contemporary physics. Because of the increasing curricular demands of atomic, quantum, solid-state, and nuclear physics, the undergraduate curriculum can no longer afford time for separate courses in many of the older disciplines devoted to such classes of wave phenomena as optics, acoustics, and electromagnetic radiation. We have endeavored to select significant material pertaining to wave motion from all these areas of classical physics. Our aim has been to unify the study of waves by developing abstract and general features common to all wave motion. We have done this by examining a sequence of concrete and specific examples (emphasizing the physics of wave motion) increasing in complexity and sophistication as understanding progresses. Although we have assumed that the mathematical background of the student has included only a year's course in calculus, we have aimed at developing the student's facility with applied mathematics by gradually increasing the mathematical sophistication of analysis as the chapters progress.