This book presents the biodiversity of the Brazilian deep-sea and its many unique geological and biological features, as well as a review of its ecology, conservation, and future research needs. The deep-sea Brazilian margin has an incredible geological heterogeneity with numerous characteristic seafloor features, and latitudinal changes in marine productivity, oceanographic conditions and biological communities have resulted in very distinct biological assemblages at regional and bathymetric scales. It is a tremendously rich ecosystem in terms of living species, from which many well-known historical tales have originated, and with unique importance for the global climate and humanity. Nevertheless, vast areas of the Brazilian margin have been explored for fishing, oil and gas, and other commodities, likely impacting a variety of deep-sea habitats at scales and intensities yet undetermined. This book is intended for students, scholars, professionals and a wide audience interested in the deep-sea in general and, more specifically, in the South Atlantic deep-sea.