This four-volume set explores the locations where the environment matters most such as where people are poor, where environments are under threat (such as on frontiers), where there are few natural resources remaining, and where industrialization is rampant. It will also explore these concerns at different system levels, from local-community, to regional, national and global. It will also explore costs of damage to the very resources on which economies rely, and the values of environmental goods and services and the controversies surrounding such valuations. It is organized around environment-people interactions (livelihoods, poverty, income, economic growth); environment-environment interactions (do people matter?); and people-people interactions (collective action challenges, institutions).