This book is about studying the acoustics of marine animals using underwater acoustic techniques. Marine bioacoustics is a very broad interdisciplinary field that covers diverse areas as the production and reception of sound by researchers, the production and reception of sound by marine animals, the nature of sound propagation in the ocean, the nature of sound propagation in small tanks and other enclosure, signal processing techniques to acquire and store acoustic signals either on tape or in a computer, the analysis of sounds produced by marine animals, the characterization of hearing and sound production by marine animals, psycho-acoustic testing procedures, electrophysiological measurement procedures to name a few. Therefore, an accomplished bioacoustician must have some knowledge not only in the physics and mathematics of sounds but in the various areas mentioned above. This book attempts to discuss and unite the various areas of marine bioacoustics in a single text in as comprehensive manner possible.