Simply and frankly American, Mary Cassatt lived in Paris for much of her life, where she defied artistic convention and painted humble subjects--most often peasant women and their children--with light, bright colors. Edgar Degas was impressed with her work and became her mentor and friend. He invited her to exhibit her work with other independent painters--including himself, Monet, and Renoir. These painters became known as the Impressionists. Cassatt...