In the years following World War II, Americans visited the national parks in unprecedented numbers, yet Congress held funding at prewar levels and park conditions steadily declined. Elimination of the Civilian Conservation Corps and other New Deal programs further reduced the ability of the federal government to keep pace with the wear and tear on park facilities. To address the problem, in 1956 a ten-year, billion-dollar initiative titled "Mission 66" was launched, timed to be completed in 1966, the fiftieth anniversary of the National Park Service. The program covered more than one hundred visitor centers (a building type invented by Mission 66 planners), expanded campgrounds, innumerable comfort stations and other public facilities, new and wider roads, parking lots, maintenance buildings, and hundreds of employee residences. During this transformation, the park system also acquired new seashores, recreation areas, and historical parks, agency uniforms were modernized, and the arrow-head logo became a ubiquitous symbol. To a significant degree, the national park system and the National Park Service as we know them today are products of the Mission 66 era. Mission 66 was controversial at the time, and it continues to incite debate over the policies it represented. Hastening the advent of the modern environmental movement, it transformed the Sierra Club from a regional mountaineering club into a national advocacy organization. But Mission 66 was also the last systemwide, planned development campaign to accommodate increased numbers of automotive tourists. Whatever our judgment of Mission 66, we still use the roads, visitor centers, and other facilities the program built. Ethan Carr'sbook examines the significance of the Mission 66 program and explores the influence of midcentury modernism on landscape design and park planning. Environmental and park historians, architectural and landscape historians, and all who care about our national parks will enjoy this copiously illustrated history of a critical period in the development of the national park system.