Ralph Waldo Emerson was an American essayist, lecturer, and poet who is considered to be a leader in the Transcendentalist movement of the mid-19th century. He is best known for his essays, such as 'NATURE' and 'Self-Reliance', which are considered to be some of the most influential works of the time. Emerson's writing style was characterized by its emphasis on individualism and non-conformity. His work has had a lasting impact on American literature and culture.