This book describes, using first-person accounts, the history of the development in the Soviet Union and, later, in Russia of an extremely important technical field and how that history was influenced by WWI, WWII, and the Cold War, by government bureaucracy, in both positive and negative ways, by the economic collapse of the Soviet Union, and most importantly, by the dedicated efforts of vast numbers of individuals, including some of the greatest scientific minds of the 20th century. It will make fascinating reading for engineers and scientists who were engaged in similar work in the West, for historians of the Cold War and of the Soviet Union, and for present day researchers who need to learn about Russian scientific contributions. Because of its importance to national security, much of the research and development effort in underwater acoustics was classified during the Cold War, both in the Soviet Union and the United States. This book presents the first declassified accounts of the development of numerous hydroacoustic systems by individuals having first-hand knowledge of the development efforts.