Book excerpt: This book is dedicated to the analysis of bottom waters flows through underwater channels of the Atlantic Ocean. The study is based on recent observations of the authors, analysis of historical data, numerical modeling, and literature review. For example, studying both the measurements from the World Ocean Circulation experiment in the 1990s and recent measurements reveals the decadal variations of water properties in the ocean. Seawater is cooled at high latitudes, descends to the ocean bottom, and slowly flows to the tropical latitudes and further. This current is slow in the deep basins, but intensifies in the abyssal channels connecting the basins. The current overflows submarine topographic structures and sometimes forms deep cataracts when water descends over slopes by several hundred meters. The flow of Antarctic Bottom Water (AABW) is studied on the basis of CTD sections combined with Lowered Acoustic Doppler Profiling (LADCP) carried out annually, and long-term moored measurements of currents. This book is a collection of oceanographic data, interpretation, and analysis, which can be used by field oceanographers, specialists in numerical modeling, and students who specialize in oceanography.