This textbook is written for mechanical engineering students at universities of applied sciences and technical universities. The content is tailored to what is essential for mechanical engineers. Particularly valuable is the clear and understandable presentation. Numerous images, diagrams, and example calculations assist readers in understanding the laws of thermodynamics and gaining confidence in their application. Therefore, this book is also suitable for self-study. The 4th edition has been expanded to include sections on cyclic processes and a review section with questions and tasks accompanied by detailed solutions.