The volume is devoted to the presentation of quantum and classical statistical physics, based on the Gibbs method. The basics of thermodynamics, the statistical physics of the ideal gas, the theory of non-ideal gases, the distribution of Fermi and Bose and their application to the thermodynamics of black radiation and solid-state theory, the theory of solutions, the theory of chemical equilibrium and surface phenomena . are presented. The magnetic properties of the gas. The theory of crystal symmetry, fluctuations, phase transitions of I and II kind and properties of matter in the vicinity of the critical point, the role of fluctuations in these phenomena are considered. , which sets forth the quantum theory of the condensed state of matter, constitutes volume IX of the course.