This book contains articles by oceanographic researchers from the (former) USSR and presents new data on various aspects of the Black Sea. The topics include Black Sea thermohaline, hydrochemical and optical structures, the dynamics of the Main Black Sea current and deep layers, wave phenomena in shelf areas and modelling of complex marine systems. Aslo included are some experimentally derived results which allow a deeper insight into the problem of O2 and H2S coexistence in the Black Sea. The commonplace notions about the structure of the oxic/anoxic interface are critically evaluated.