George Santayana, poet, philosopher, and literary and cultural critic, was one of the key figures in classical western philosophy. He was a man before his time . . . before the popularization of naturalism, multiculturalism, philosophy as literature, and spirituality without being a religious believer. "The Sense of Beauty" is a primary source for the study of aesthetics. Critics have described it as a milestone in aesthetic theory. Santayana's writings are thematically full of the relationships between literature, art, religion, and philosophy.