Studies of convection in geophysical flows constitute an advanced and rapidly developing area of research that is relevant to problems of the natural environment. Since the late 1980s, significant progress has been achieved in the field as a result of both experimental studies and numerical modelling. This led to the principal revision of the widely held view on buoyancy-driven turbulent flows comprising an organized mean component with superimposed chaotic turbulence. An intermediate type of motion, represented by coherent structures, has been found to play a key role in geophysical boundary layers and in larger scale atmospheric and hydrospheric circulations driven by buoyant forcing. New aspects of the interaction between convective motions and rotation have recently been discovered and investigated at the end of the 20th century. Extensive experimental data have also been collected on the role of convection in cloud dynamics and microphysics. New theoretical concepts and approaches have been outlined regarding scaling and parameterization of physical processes in buoyancy-driven geophysical flows. The book summarizes interdisciplinary studies of buoyancy effects in different media (atmosphere and hydrosphere) over a wide range of scales (small scale phenomena in unstably stratified and convectively mixed layers to deep convection in the atmosphere and ocean), by different research methods (field measurements, laboratory simulations, numerical modelling), and within a variety of application areas (dispersion of pollutants, weather forecasting and hazardous phenomena associated with buoyant forcing).