The book contains a collection of papers presented at the 1989 International Conference of the Systems Dynamics Society in Stuttgart. It presents the state of the art in systems research and computer simulation modeling for the analysis and design of complex systems. The interdisciplinary and cross-disciplinary oriented contributions accentuate the potential benefits of well designed simulation experiments. The structure of the volume follows the conference programm. Papers presented in the Plenary Sessions, deal with the impact of systems thinking on management in general. They underline the need for a "New Management Style" to utilize to potential of formal models combined with advanced computer technology. The increasing size and complexity of problem situations cannot be coped with in a more intuitive manner. Other parts of the volume discuss applications of Systems Dynamics to business strategy, macro-economic policy, government planning etc. Methodological aspects are treated in sections on optimization of complex systems, teaching and training of such a systems approach is treated in an appropriate proportion.