This book constitutes a refereed post-workshop selection of papers presented at the 6th International Workshop on Computer-Aided Systems Theory, EUROCAST'97, held in Las Palmas de Gran Canaria, Spain, in February 1997. The 50 revised full papers presented were carefully selected for inclusion in the volume. The book is divided into sections on design environments and tools, theory and methods, engineering systems, intelligent systems, signal processing, and specific methods and applications.