There has been significant progress in tsunami research, monitoring and mitigation within the last decade. This book summarizes the state-of-the-art knowledge on tsunamis. It presents a comprehensive overview of tsunamis, seaquakes and other catastrophic ocean phenomena. It describes up-to-date models of tsunamis generated by a submarine earthquake, landslide, volcanic eruption, meteorites impact, and moving atmospheric pressure inhomogeneities. Models of tsunami propagation and run-up are also discussed. The book investigates methods of tsunami monitoring including satellite altimetry and the study of paleotsunamis. Non-linear phenomena in tsunami source are discussed in the context of their contribution to the wave amplitude and intensification of the vertical exchange in ocean. The book is intended for scientists, researchers and specialists in oceanography, geophysics, seismology, hydro-acoustics, geology, geomorphology, including the engineering and insurance industries.