The National Park Service was established in 1916 to administer America’s finest scenic areas. It set a worldwide example of how to preserve wilderness for future generations. This journal describes a variety of National Parks and other NPS sites, chosen for their scenic value and geologic history. The authors are specialists who have studied these areas for decades, and their perspectives will interest anyone who cherishes nature. Highlighted sites include Grand Canyon, Obed Wild and Scenic River, Death Valley, Mammoth Cave, Carlsbad Caverns, Hawaii Volcanoes, and caves of the Black Hills, Big Bend, Wupatki, and Everglades. These and several other parks and monuments are illustrated by fine color photographs, maps, and diagrams. The chapters on caves illustrate their exceptional diversity, history, relationships to their surroundings, and complex origins. This issue includes a Quiz that uses early maps as the basis for questions about the geography of western National Parks. Each chapter illustrates the greatest challenge faced by the National Park Service – to present these unique sites to the public in an informative way, while at the same time preserving their integrity.