Human-induced environmental change is to be found throughout the world, but there are areas that scientists consider to be "critical regions" - regions that are particularly vulnerable to or suffering from environmental degradation. In this volume nine such "critical environmental regions" (Amazonia, the Aral Sea basin, the middle mountains of Nepal, Kenya's Ukambani region, the US Southern High Plains, the Mexico Basin, the North Sea, the Ordos Plateau of China, and the eastern Sundaland region of South-East Asia) are examined as case-studies. In chapter one the authors provide a detailed look into the concepts of environmental criticality and endangerment and propose formal definitions. The nine regional studies that follow in the subsequent chapters serve to translate the conceptual framework into the physical and social realities of each area. The case-studies make available an up-to-date synthesis of vast amounts of inaccessible data, and as such will be valuable to scholars and policy makers interested in specific areas of the world and others interested in regional comparisons. Anyone concerned with global environmental change, criticality, human-environment interactions, and how societies in different regions have responded to environmental degradation will find much that is new and important in this pioneering, innovative study.