The fundamentals of thermodynamics for environmental purposes are set out. The applications of thermodynamics with its modern achievements and methods are considered for solution of many applied problems in environmental science. It is shown that the neglect of scientific recommendations increases the human pressure on the environment. Attention is paid to systems far from equilibrium, in which a small input signal can cause a strong response at the output, as well as self-organization processes. The textbook will be useful for students, graduate and postgraduate students studying in the field of ecology, geoecology and environmental science.