Agriculture is changing rapidly all over the world. Intensification, diversification, optimizing scarce resources, integrated pest management, sustainability and climate change are key issues for agricultural institutes. The best solutions will be found by integrating disciplines. Organized thinking about future farming requires forecasting of the implications of alternative ways to farm and to develop agriculture. Systems thinking and systems simulation are indispensable tools for such integration and extrapolation. About 150 scientists and senior research leaders from all over the world participated in the symposium `Systems Approaches for Agricultural Development’ to discuss these issues. The symposium reviewed the status of systems research and modeling in agriculture, with special reference to evaluating their efficacy and efficiency for achieving research goals, and to their application in developing countries, promoted international cooperation in modeling, and increased awareness of systems research and simulation. This book comprises the papers on the technical subjects. Well informed authors describe and illustrate how systems research was used to improve agricultural production systems of all continents and in diverse environments.