Mathematical modeling and computer simulation make it possible to understand and control the dynamic processes taking place in complex systems. Simulation provides insights into the often surprising diversity of possible behaviors, and allows identifying possibilities for intervention and options for alternative development. About one hundred simulation models from all areas of life are fully documented in the three volumes of the 'System Zoo'. They can be quickly implemented and easily operated using freely available system dynamics software. Volume 2 of the System Zoo contains simulation models of the regional water cycle and global carbon cycle, the photosynthesis of vegetation, forest growth, the water, nutrient, and energy dynamics of agriculture, the interaction of plants, animals, and humans with other organisms and resources by predation, harvesting, and competition for nutrients, and through utilization of renewable and exploitation of nonrenewable resources. The System Zoo collection of simulation models is particularly well-suited for teaching, training, and research projects at all levels from high school to university, and for individual study. Volume 1 of the System Zoo contains simulation models of elementary systems, and of systems from the fields of physics and engineering. Volume 3 deals with systems and processes found in economy and society, and with long-term global development. Hartmut Bossel is Professor Emeritus of environmental systems analysis. He taught for many years at the University of California in Santa Barbara and the University of Kassel, Germany, where he was director of the Center for Environmental Systems Research until his retirement. He holds an engineering degree from the Technical University of Darmstadt, and a Ph.D. degree from the University of California at Berkeley. With a background in engineering, systems science, and mathematical modeling, he has led many research projects and future studies in different countries, developing computer simulation models and decision support systems in the areas of energy supply policy, global dynamics, orientation of behavior, agricultural policy, and forest dynamics and management. He has written numerous books on modeling and simulation of dynamic systems, social change and future paths, and has published widely in the scientific literature in several fields.