Ocean acoustics represents an auxiliary science of ocean research, providing indispensable tools for the survey of structure, motion and features of undersea matter. The book includes the fields of research, off-shore industry and economy, of governmental surveillance, and protection of the ocean and shelf areas. The combined potential of large scale area coverage and advanced high resolution methods is unique. The book concentrates on imaging methods of acoustic remote sensing in the sea, which demonstrate both the peerless power and fascinating aesthetics of ocean acoustic visualization. It shows ocean acoustics as the unique technology to visualize in detail the interior of more than two thirds of the surface of the globe. Today technologies to "see by sound" reveal the convincing evidence of the various processes of geodynamics, the rise and set of continental plates, the results of enormous forces of deformation. Sediment echosounders look into the fine structure of the sea floor stratification, the prehistoric diary of the earth climate, disclose subsediment morphologies and discover large deposits of methane ice. The CD included with the book allows turning and zooming of the relief globe as well as of selected large sound images and contains animations, underwater flights and soundtracks.