This book covers the various aspects of the development of an integrated product and process modelling system using advanced computer technologies. It describes languages and methodologies for developing an information reference model, system architectures, a link with emerging new standards such as ISO/STEP and CIM/OSA, and a new approach for the definition of model semantics. It discusses practical aspects of the usage and integration of computer aided design, planning and production systems, and shows how the reference model can be applied. Concrete practical examples are given for two demonstration parts: a sheet metal part and a ship propeller blade. Much attention has been devoted to making the subject matter easy to understand for a wide audience. The reference model is presented in easy-to-grasp chunks in a graphical, informal way, and many figures support the text. The reader should gain a clear impression of the various technical aspects of CIM systems using modern techniques corresponding to emerging new standards. Aspects of future systems are also included.