The field of acoustics is of immense industrial and scientific importance. The subject is built on the foundations of linear acoustics, which is widely regarded as so mature that it is fully encapsulated in the physics texts of the 1950s. This view was changed by developments in physics such as the study of quantum chaos. Developments in physics throughout the last four decades, often equally applicable to both quantum and linear acoustic problems but overwhelmingly more often expressed in the language of the former, have explored this. There is a significant new amount of theory that can be used to address problems in linear acoustics and vibration, but only a small amount of reported work does so. This book is an attempt to bridge the gap between theoreticians and practitioners, as well as the gap between quantum and acoustic. Tutorial chapters provide introductions to each of the major aspects of the physical theory and are written using the appropriate terminology of the acoustical community. The book will act as a quick-start guide to the new methods while providing a wide-ranging introduction to the physical concepts.