Pearl Buck's 1938 Nobel Prize in Literature was the third such prize awarded to an American. The daughter of American missionaries to China, who later worked as a missionary herself, Buck is best known for her novels set in China. The Good Earth (1931), was the first in her House of Earth trilogy. The other two works include Sons, published the following year, and A House Divided (1935). After writing twin biographies of her mother and father, she began to publish more rapidly. Beginning in about 1942, her works became increasingly propagandistic relative to the Japanese invasions of China during the 1930s.