Thermodynamics is a subject that all engineering students have to face and that most of them treat with great respect. This makes it all the more important to offer a good and easy-to-understand approach to the laws of energy conversion. This is what this textbook is intended to do: It covers the basics of classical technical thermodynamics as they are typically taught at universities: The first and second law of thermodynamics as well as equations of state are explained for idealized and real fluids which are subject to a phase change. Thermodynamic mixtures, e.g. humid air, are treated as well as chemical reactions. Components and thermodynamic