This book presents the results of extensive research in computer-supported decision processes in engineering,carried out over many years by the author and his coll- orators. The author has cooperated with designers in Poland and in Germany. Very often there was university–industry cooperation for the building of speci?c so- ware for certain engineering tasks. The majority of the concepts,for example “the designer’s personal assistant”and the decomposition and coordination of multicriteria decision problems, evolved through cooperation with designers in this ?eld. The author,while working together with them,understood that this group of people is characterised by a strong in- vidualism and that the range of applied approaches and methods is wide. The most signi?cant in?uences on the author’s opinions through contact with the designers were the lectures he delivered for more than 12 years for post-graduate studies on computer-aided design in machinery. The lectures included seminars which required the creation of concepts for an individual computer support system for decision processes,generally well known to the designers who participated in the lectures. In the theoretical part the characteristics of the actual computer-aided design and engineering (CAD and CAE) tools were depicted,whereas in the practical part the students created concepts of computer environments for the realisation of design projects in their own professional work. The task was con?ned to the expr- sion of the design process.