The book aims at the stability of stationary convective flows; the authors pay the main attention to the plane-parallel flows, by means of which the instability mechanisms and the properties of the perturbation spectrum are investigated. The influence of some complicating factors, such as the stratification, the dependence of viscosity on temperature and the heat properties of boundaries are analyzed. The convective flows of binary gas mixtures, the electrically conducting, dielectric and non- Newtonian fluids and media with impurity are studied with respect to their stability. The authors discuss the advective, vibro-convective and combined flows and the flows generated by the inner heat eduction of various nature. Finally the stability of convective boundary layers, of closed flows and secondary regimes is considered. The monograph is assigned to the specialists on convection and hydrodynamical stability.