This book covers the classical areas of technical thermodynamics: The first part deals with the basic equations for energy conversion and idealized fluids. The second part deals with real fluids, which can be subject to a phase change, for example. Furthermore, thermodynamic mixtures of fluids are considered, e.g., humid air and gas mixtures. In the last part of the book, combustion processes and chemical reactions are presented and thermodynamically balanced. In each chapter, there are examples and exercises to deepen the theoretical knowledge. In this third edition of the textbook, a chapter on thermodynamics of mixtures has been added. This includes both gas and liquid mixtures, which are considered ideal and real. Equilibrium conditions and state functions are derived step by step and discussed using the example of binary mixtures. The book is aimed at students of mechanical engineering and professional engineers.