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. Professor Boris W. Levin is a Corresponding Member of the Russian Academy of Sciences and Director of the Institute of Marine Geology and Geophysics, Far East Branch of RAS, in Yuzhno-Sakhalinsk, Russia. He is a member of IUGG Tsunami Commission, American Geophysical Union, Seismological Society of America and National Geographic Society. He has more than 200 scientific publications in the fields of geophysics, tsunamis, seaquakes, seismology. Mikhail A. Nosov is a Professor of Physics of Sea and Inland Waters at the Faculty of Physics of M.V. Lomonosov Moscow State University, Russia. He is an active participant to the EGS and EGU meetings. As co-convener and UNESCO contractor, he organized the International Workshop on "Local Tsunami Warning and Mitigation" (2002). In 2005 he was awarded Plinius Medal of European Geosciences Union. He has more than 50 scientific publications in the fields of marine physics, tsunamis, seaquakes.