John Burroughs (April 3, 1837 – March 29, 1921) was an American naturalist and essayist important in the evolution of the U.S. conservation movement. According to biographers at the American Memory project at the Library of Congress, John Burroughs was the most important practitioner after Thoreau of that especially American literary genre, the nature essay. By the turn of the century he had become a virtual cultural institution in his own right: the Grand Old Man of Nature at a time when the American romance with the idea of nature, and the American conservation movement, had come fully into their own.