Existing texts on artificial intelligence expert systems and knowledge-based systems on the whole treat only narrow application domains, while many practising engineers use expert systems to solve complicated design problems. The theme of this book is to extend the range of problem solving by the use of cooperating expert design systems. It is concerned with the theory and implementation of a computational infrastructure that enables system designers to achieve the requisite trade-offs for a good overall balance of design among, for example, heterogeneous design tools. Case studies are included.