Process Engineering is based on almost 30 years of practical experience of the author in process simulation, design and development. The book is a missing link between students and practitioners. The author has coached many graduates in their first months and knows what the typical questions are. Coming from the university, graduates often do not know which relevance their knowledge has and how to apply it in real life, whereas established practitioners often stick to the narrow way of their experience, forgetting that science continuously makes progress. There is a gap to be bridged. From his own professional experience, the author covers many topics of the process engineering business, but three guest contributions are a valuable supplement to the content of the third edition. Already in the 2nd edition, Verena Haas from BASF SE wrote an excellent chapter on dynamic process simulation. For the new 3rd edition, Gökce Adali and Michael Benje added two chapters on digitalization and patents, respectively. Preparing the reader for the everyday business!