This book presents a systematic description of the knowledge accumulated on the physical oceanography, marine chemistry and pollution, marine biology and geology, meteorology and hydrology of the Black Sea. It presents the principal characteristic features of the environmental conditions of the sea and their changes in the second half of the 20th century. At present, the principal problems of the Black Sea are related to the estimation of the intensity of the chemical pollution of the sea and its impact upon the biota. Special attention is given to the socioeconomic, legal, and political issues in the Black Sea region. This publication is based on numerous observational data collected by the authors of the various chapters during sea expeditions, on the archive data of several Russian and Ukrainian oceanographic institutions, as well as on a large body of scientific literature, mainly published in Russian editions. This book is aimed at specialists concerned with research in the various fields of physical oceanography, marine chemistry, pollution studies, and biology whose work involves solving a wide range of problems from regional climate to mesoscale processes, and who use a variety of methods from remote sensing of the seas to numerical and laboratory modeling.