The book provides a systematic introduction into the fundamental ideas of thermodynamics at a somewhat advanced level. And it exhibits many applications of the theory in the fields of engineering, physics, chemistry, physical chemistry, and materials science. The universal equations of balance are strictly separated from the constitutive equations which characterize the behavior of material bodies, mostly gases, vapors, and liquids. Some selected solids like rubber, gels and shape memory alloys are considered as well. Both authors have taught students of the subject for many years at the Technical University of Berlin, and they have actively participated in modern research in thermodynamics. Historical annotations offer some relaxing moments for the reader.