Although the application of systems approaches in agricultural research and natural resource management is a rather new field, there is already increasing demand for implementation of these approaches. This will require a critical mass of specialists in national agricultural research systems and international agricultural research centers. While these institutions are setting themselves up for systems research, the experience that has been gained in this area needs to be evaluated, further possibilities need to be explored, and new objectives and targets need to be set. This book contains the papers of a three-day seminar on systems approaches and modelling for agricultural development. The seminar, which was held at ISNAR and co-organized by ICASA, was attended by participants from 12 national agricultural research systems, nine international agricultural research centers, and five advanced research organizations. In 24 chapters the book assesses the state of the art of systems approaches in agricultural research, resource management, and rural planning, and gives an impression of the evolution of this interdisciplinary field and its use.