This book documents the development of a concurrent CAD system. It summarizes the work carried out in ESPRIT Project 5168 Computer Aided Concurrent Integral Design (CACID). All phases of the development of the system are described, including aspects of the user interface design and the system data model. The use of modern object-oriented software tools such as the ACIS geometry modeller, the object-oriented database system ObjectStore, the programming language C++ and the user interface class library InterViews are treated from the viewpoint of a software developer. The requirements of a small mechanical engineering company are described as well as the design of product data models for the new CAD system. This is the first such presentation of a concurrent CAD system. BITTE U4-TEXT FUR WERBEMITTEL VERWENDEN!