Through a rich interpretation of the remarkable photographs W. E. B. Du Bois compiled for the American Negro Exhibit at the 1900 Paris Exposition, Shawn Michelle Smith reveals the visual dimension of the color line that Du Bois famously called "the problem of the twentieth century." Du Bois's prize-winning exhibit consisted of three albums together containing 363 black-and-white photographs, mostly of middle-class African Americans from Atlanta and...