The book outlines the basic laws of thermodynamics and their application to ideal and real working bodies. Attention is paid to the main provisions on forward and reverse cycles, exergy, direct conversion of heat into electrical energy, the basics of chemical thermodynamics of solutions. The third edition (2nd - 1981) additionally sets out the basics of plasma and solid thermodynamics, cycles with real working bodies, elements of statistical thermodynamics, outflow from blood vessels and other issues.