Henry David Thoreau was an American author, poet, naturalist, tax resister, surveyor, historian, philosopher, and leading transcendentalist. He is best known for his book Walden. He was deeply interested in the idea of survival in the face of hostile elements, historical change, and natural decay. He was a strong abolitionist and his belief in a philosophy of civil disobedience influenced the political thoughts and actions of such later figures as Leo Tolstoy, Mahatma Gandhi, and Martin Luther King, Jr. This spiritual autobiography of a practical record his life at the Walden Pond Retreat, his detailed observations of nature, and his comments on the world's problems.