This volume brings together the understanding and the judgment of the world's scientific community on the issues of highest priority for the future of the environment and development. It looks beyond the state of the art and formulates the environment and development research agenda and identifies the scientific knowledge base that will be needed for rational policy decisions during the coming decades. Diverse topics such as population, land use, energy, and global cycles are covered under sixteen themes that have been grouped into three sections: "Problems of Environment and Development" "Scientific Understanding of the Earth System" and "Responses and Strategies".