Whiteness studies is an interdisciplinary arena of inquiry that has developed beginning in the United States, particularly since the late 20th century, and is focused on what proponents describe as the cultural, historical and sociological aspects of people identified as white, and the social construction of whiteness as an ideology tied to social status. Pioneers in the field include W. E. B. Du Bois ("Jefferson Davis as a Representative of Civilization"; 1890; Darkwater, 1920), James Baldwin (The Fire Next Time, 1963), Theodore W. Allen (The Invention of the White Race, 1976, expanded in 1995), Ruth Frankenberg (White Women, Race Matters: The Social Construction of Whiteness, 1993), author and literary critic Toni Morrison (Playing in the Dark: Whiteness and the Literary Imagination, 1992) and historian David Roediger (The Wages of Whiteness, 1991). By the mid-1990s, numerous works across many disciplines analyzed whiteness, and it has since become a topic for academic courses, research and anthologies.