1. Introduction. Classification of chromatography methods. Principles of construction of gas chromatographs. References. 2. Elements of Chromatography with Gas Mobile Phase. The mechanism of separation in gas chromatography. Retention parameters. Theories of gas chromatography. References. 3. Thermodynamics of Solutions as Related to Gas-Liquid Chromatography. Quantities of solution thermodynamics. Statistical models of solutions. Application of models to gas-liquid chromatography. References. 4. Thermodynamics of Direct Gas Chromatography. Thermodynamics of dissolution. Thermodynamics of adsorption at a gas-solid interface. Thermodynamics of vaporization. Molecular properties of single substances. 5. Thermodynamics of Inverse Gas Chromatography. Thermodynamics of dissolution. Thermodynamics of adsorption. Phase transitions. Glass transitions. Other second order transitions in polymers. Determination of diffusion coefficients. Segregation of block copolymers. Other applications of inverse gas chromatography. References. Subject Index.