This chapter presents a summary of the methodology and results of a comprehensive global assessment of the world's agricultural ecology. The national-level information with global coverage enables knowledge-based decisions for sustainable agricultural development. The Agro-ecological Zones approach is a GIS-based modeling framework that combines land evaluation methods with socioeconomic and multiple-criteria analysis to evaluate spatial and dynamic aspects of agriculture. The results of the Global AEZ assessment are estimated by grid cell and aggregated to national, regional, and global levels. They include identification of areas with specific climate, soil, and terrain constraints to crop production; estimation of the extent and productivity of rain-fed and irrigated cultivable land and potential for expansion; quantification of cultivation potential of land currently in forest ecosystems; and impacts of climate change on food production, geographical shifts of cultivable land.