Four-part treatment covers principles of quantum statistical mechanics, systems composed of independent molecules or other independent subsystems, and systems of interacting molecules, concluding with a consideration of quantum statistics.

Part I deals with principles of quantum statistical mechanics. Part II examines systems composed of independent molecules or other independent subsystems. Part III considers systems of interacting molecules, and Part IV covers quantum statistics and includes sections on Fermi-Dirac and Bose-Einstein statistics, photon gas, and free-volume theories of quantum liquids.