The present book represents an outstanding text and reference for a very broad audience of senior undergraduate and graduate students, researchers, and practitioners, who are involved in the field of underwater sound - its physical background, today's engineering applications, and its modern important related areas of oceanography, remote sensing, biological characteristics, underwater communications.The internationally renowned authors, Medwin and Clay, have produced a work that reflects the tremendous development in the field over the past two decades, and importantly, addresses it in the broadest possible way, emphasizing its current highly interdisciplinary nature.The reader is given various techniques to solve not merely the "direct problem," for example, to predict the propagation of sound from an essential knowledge of the physical and biological data along the ocean propagation path; but also to find solutions to "inverse problems," whereby the vagaries of underwater sound propagation are used to measure the physical characteristics of the ocean and its boundaries-and sense its fish and zooplankton inhabitants.The book's modern, authoritative nature, its breadth of coverage, and its extensive bibliography-from the earliest use of sound in the sea to present references-make it a unique source for today's acousticians, ocean engineers, physical oceanographers, marine biologists, and for every other individual who wishes to use acoustics to learn more about their fields.