Aaron Sachs is Professor of History and American Studies at Cornell University. He is the author of “The Humboldt Current: Nineteenth-Century Exploration and the Roots of American Environmentalism,” “Arcadian America: The Death and Life of an Environmental Tradition,” and “Up from the Depths: Herman Melville, Lewis Mumford, and Rediscovery in Dark Times.” With John Demos, he edited ‘Artful History: A Practical Anthology.” He lives in Ithaca, New York, with his wife, three children, and two cats. Occasionally there’s a woodchuck in the backyard.