Physical Acoustics: Principles and Methods reviews the principles and methods of physical acoustics and covers topics ranging from relaxation processes in sound propagation in fluids to acoustic vibrational modes in quartz crystals, along with electron and phonon drag on mobile dislocations in metals at low temperatures. Two-pulse phonon echoes in solid-state acoustics and memory echoes in powders are also discussed. Comprised of seven chapters, this volume begins with a historical account of relaxation processes in sound propagation, followed by an analysis of acoustic vibrational modes in quartz crystals. The reader is then introduced to electron and phonon drag on mobile dislocations at low temperatures, together with two-pulse phonon echoes in solid-state acoustics and dynamic polarization echoes in powdered materials. The book also considers memory echoes in powders before concluding with an evaluation of acousto-optic transduction mechanisms used in fiber optic acoustic sensors, together with their practical implementation. This book will be of interest to physicists.