This book treats the structure and variability of basic physical fields in a thin near-surface layer which responds quickly to all short-term and local fluctuations of atmospheric forcing and of radiative solar energy flux. The book contains up-to-date information on different phenomena and processes in this layer based on research conducted over the last ten years. The following topics are treated in detail: basic types of vertical thermal structure of near-surface layers; anomalous phenomena on the ocean surface; thermal and haline boundary layers, its structures and relations to convection; diurnal thermocline and cycle nature of related processes; effects of precipitation on near-surface salinity and thermal structure; peculiarities of near-surface ocean currents; coherent (organized) forms of non-stationary currents (mushroom currents or vortex dipoles, transversal jets in coastal upwellings, vortices and jets in marginal ice zones); some aspects of effectiveness of remote sensing of the ocean by aerospace technique.