In this provocative walking meditation, writer and former park ranger 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. 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...