From the introduction: Emphasizing an integrated approach to environmental earth science through problem-based learning, the module asks students to assume the role of environmental biologist, and help several government agencies resolve the debate surrounding "let it burn" policies in national parks. The government agencies would like to know whether or not to allow naturally occurring fires in Yellowstone National Park to burn to their natural conclusion. The agencies are particularly interested in student recommendations based on an Earth System Science (ESS) analysis of a fire's impact on the air, land, water, and living things. Many of the pages within the site provide hyperlinked background resources to investigate wildland fire issues in more detail. A glossary, references, related links, and a general description of the problem-based learning model compliment the site.