Book excerpt: Yellowstone National Park is the focal point of the 22-million-acre, multifaceted Greater Yellowstone Ecosystem, located in northwestern Wyoming and in parts of eastern Idaho and Montana. Yellowstone has a uniquely American identity as a place where nature--largely untouched and unmanaged--is allowed to flourish. This is a detailed survey that blends Yellowstone's past into its present and explores its likely future. It covers the first inhabitants of the area; the explorers and visionary conservationists who first brought Yellowstone to public attention; the unsung early heroes of the park's ranger service; and the flora, fauna, and spectacular geology of the region. The book also covers the possible future paths for the park in light of global climate change.