Henry David Thoreau (July 12, 1817 – May 6, 1862) was an American naturalist, essayist, poet, and philosopher.A leading transcendentalist,he is best known for his book Walden, a reflection upon simple living in natural surroundings, and his essay "Civil Disobedience" (originally published as "Resistance to Civil Government"), an argument for disobedience to an unjust state.