This textbook is a good overview of most of the aspects of underwater acoustics. It is comprehensive and covers some of the underwater acoustics fundamentals such as propagation, sound velocity profiles and their influence, background noise, scattering and target strength, absorption, transducers, arrays and array processing. In addition, it also covers applications of underwater acoustics—sonar, passive and active, sonar imaging, navigation aids, sub-bottom profiling, acoustic communications—including a discussion of the parameters that control the quality of the information in the application due to the effects of background noise, propagation and other underwater acoustics phenomena. In a chapter it treats underwater acoustics associated with marine mammals which is mostly descriptive, as one would expect, with data related to the hearing of mammals (audiograms), type and intensity of sound generated by mammals and the impact of natural and man-made sounds on the behavior of mammals. The material is presented in a way that allows someone who is not so familiar with underwater acoustics can use the book to gain a good background knowledge. Furthermore the book contains sufficient details so it can be used as a reference. While the textbook in general has all the right information, there are comments sprinkled throughout that may lead to a person to gain the wrong impression.