Herbert Baur provides a simple description of the theory of thermophysics of polymers. In order to illustrate the theoretical skeleton he has only treated the simple, easily comprehensible problems of polymer physics. These, however, in detail. The main points covered are: thermally excited conformation isomery of polymers; phonon gas of ideal polymer crystals; the dissipative thermo-mechanical behavior of polymers, new aspects of viscoelastic behavior, glass transistion, and crystallization.