On March 22, 1958 David Brower's film Wilderness Alps of Stehekin premiered to an audience of conservationists in Seattle, Washington. Almost two years in the making, the thirty-one minute film advocated the preservation of nature in Washington's North Cascades through the creation of a national park. Over the next decade, Wilderness Alps of Stehekin became the most influential publicity tool in the struggle to preserve the North Cascades. Because of the region's geographic isolation, the film was the first time many people throughout the nation were exposed to the scenic grandeur of the area. Images of craggy peaks and colorful alpine meadows resonated deeply with many Americans and persuaded them to join in the campaign. It was the voice of these citizens that led Congress to pass the North Cascades Act of 1968, which placed 674,000 acres of the North Cascades under the jurisdiction of the National Park Service. In this thesis I tell the creation story of North Cascades National Park from a conservationist perspective and trace the influence of Wilderness Alps of Stehekin within this context. Although the film was never shown in movie theaters and never aired on national television, many thousands viewed it from its premiere to the signing of the North Cascades Act. The film first introduced the idea of a North Cascades National Park, and it was important in convincing conservationists to unite around a national park solution. Ultimately, Wilderness Alps of Stehekin changed the approach activists took in the North Cascades and helped to preserve a wild and scenic nature experience for future generations through the protection of old-growth forests and alpine meadows.