This textbook is based on the VDI guidelines 2221 and 2222. Starting from the description of the operational classification of design, it clearly illustrates how, based on systems engineering, the activity of designing can be carried out efficiently, purposefully, and with optimal results, supported by methodologies. The most essential methods to be applied are described. The main focuses are on the topics of functional structure and cost-effective design, with a strong practical relevance. This book serves as a reliable guide for students, as well as engineers and technicians, and enables quick access to methodological design. In the current edition, the chapters on the steps of the design process, task definition, and conceptualization have been revised; additionally, many images have been qualitatively improved.