From John Muir to David Brower, from the creation of Yellowstone National Park to the Endangered Species Act, environmentalism in America has always had close to its core a preservationist ideal. Generations have been inspired by its ethos—to encircle nature with our protection, to keep it apart, pristine, walled against the march of human development. But we have to face the facts. Accelerating climate change, rapid urbanization, agricultural and industrial devastation, metastasizing fire regimes, and other quickening anthropogenic forces all attest to the same truth: the earth is now spinning through the age of humans. After Preservation takes stock of the ways we have tried to both preserve and exploit nature to ask a direct but profound question: what is the role of preservationism in an era of seemingly unstoppable human development, in what some have called the Anthropocene?