Ralph Waldo Emerson was an American essayist, lecturer, and poet who led the Transcendentalist movement of the mid-19th century. He was a champion of individualism and a prescient critic of the countervailing pressures of society, and he disseminated his thoughts through dozens of published essays and more than 1, 500 public lectures across the United States. Emerson is also well known for his friendship with Henry David Thoreau and his influence on other writers and thinkers.