In the wake of the devastating 1906 earthquake and fire, the city of San Francisco desperately needed reliable supplies of water and electricity. Its mayor, James Phelan, pressed for the damming of the Tuolumne River in the newly created Yosemite National Park, setting off a firestorm of protest. For the first time in American history, a significant national opposition arose to defend and preserve nature, led by John Muir and the Sierra Club, who...