Henry David Thoreau (July 12, 1817 – May 6, 1862) was an American author, poet, philosopher, abolitionist, naturalist, tax resister, development critic, surveyor, and historian. A leading transcendentalist, Thoreau is best known for his book Walden, a reflection upon simple living in natural surroundings, and his essay Resistance to Civil Government (also known as Civil Disobedience), an argument for disobedience to an unjust state.