This book constitutes the thoroughly refereed post-workshop proceedings of the 7th International Workshop on Computer Aided System Theory, EUROCAST'99, held in Vienna, Austria in September 1999. The 49 revised full papers presented together with three survey contributions were carefully selected and revised for inclusion in the book. The papers are organized in topcial sections on conceptual frameworks, methods, and tools; intelligent robots; modeling and simulation; systems engineering and software development; and artificial intelligence systems and control.