Nella Larsen s novels Quicksand (1928) and Passing (1929) document the historical realities of Harlem in the 1920s and shed a bright light on the social world of the black bourgeoisie. The novels greatest appeal and achievement however is not sociological but psychological. As noted in the editor s comprehensive introduction Larsen takes the theme of psychic dualism so popular in Harlem Renaissance fiction to a higher and more complex level displaying a sophisticated understanding and penetrating analysis of black female psychology.