In this provocative walking meditation, forest ranger and writer William Tweed takes us to California's spectacular High Sierra to discover a new vision for our national parks as they approach their 100th anniversary facing dramatic changes. Tweed, who worked among the Sierra Nevada's big peaks and big trees for more than thirty years, has now hiked more than 200 miles along California's John Muir Trail in a personal search for answers: How do we address the climate change we are seeing even now--in melting glaciers in Glacier National Park, changing rainy seasons on Mt Rainer, and more fire in the West's iconic parks. Should we intervene where we can to preserve biodiversity? Should the parks merely become ecosystem museums that exhibit famous landscapes and species? Tweed weaves his experiences along this high-altitude trail together with reflections on the people and ideas that created the parks and on their status and meaning today. Asking how we can make these magnificent parks relevant for the next generation, Tweed's journey ultimately shows why we must do just that.