Book excerpt: Now in a fully updated edition, this invaluable reference work is a fundamental resource for scholars, students, conservationists, and citizens interested in America's national park system. The extensive collection of documents illustrates the system's creation, development, and management. The documents include laws that established and shaped the system; policy statements on park management; Park Service self-evaluations; and outside studies by a range of scientists, conservation organizations, private groups, and businesses. A new appendix includes summaries of pivotal court cases that have further interpreted the Park Service mission.