The textbook outlines the methodological foundations for solving problems in the section "Molecular Physics and Thermodynamics" from the course of general physics. A detailed solution of a number of standard problems, analysis and interpretation of the results obtained, and an assessment of the correctness of the solutions obtained are provided. Each chapter begins with a brief presentation of the theory, which focuses on the physical nature of the laws and principles of problem solving. Clear formulations of laws and definitions of physical quantities are given. The manual includes elements of statistical, chemical and hierarchical thermodynamics, where issues of the thermodynamics of polymers and living systems are discussed. The book is intended for university students studying general physics, and for teachers conducting seminars and practical classes in the section “Molecular Physics and Thermodynamics”, as well as may be useful for a wide range of specialists and individuals engaged in self-education.