The book outlines the main questions of the theory of heat exchange. The problems of convective heat exchange and issues related to new equipment (non-isothermal flows, boundary layer in turbomachines, liquid metal coolants, supersonic gas flow, heat exchange in rarefied gas, when the state of aggregation changes, etc.) are considered. Particular attention is paid to the physical interpretation of heat exchange patterns, the basics of thermal calculation of devices, some methods of thermal protection of machine elements are given.