Ecosystems and Human Well-Being is the first product of the Millennium Ecosystem Assessment, a four-year international work program designed to meet the needs of decisionmakers for scientific information on the links between ecosystem change and human well-being. The book offers an overview of the project, describing the conceptual framework that is being used, defining its scope, and providing a baseline of understanding that all participants need to move forward. The Millennium Assessment focuses on how humans have altered ecosystems, and how changes in ecosystem services have affected human well-being, how ecosystem changes may affect people in future decades, and what types of responses can be adopted at local, national, or global scales to improve ecosystem management and thereby contribute to human well-being and poverty alleviation. The program was launched by United National Secretary-General Kofi Annan in June 2001, and the primary assessment reports will be released by Island Press in 2005. Leading scientists from more than 100 nations are conducting the assessment, which can aid countries, regions, or companies by: providing a clear, scientific picture of the current state of Earth's ecosystems at multiple scales; deepening our understanding of the relationship and linkages between ecosystems and human well-being, including economic, social and cultural aspirations; demonstrating the potential of ecosystems to contribute to poverty reduction and enhanced well-being; offering scenarios of our future human and ecological well-being; identifying and evaluating policy and management options for sustaining ecosystem services and harmonizing them with human needs; The Millennium Assessment is an invaluable new resource for professionals and policymakers concerned with international development, environmental science, environmental policy, and related fields. It will help both in choosing among existing options and in identifying new approaches for achieving integrated management of land, water, and living resources while strengthening regional, national, and local capacities. It will also improve policy and decisionmaking at all levels through improved collaboration between natural and social scientists, and between scientists and policymakers. Ecosystems and Human Well-Being is an essential introduction to the project.