• The problem of the twentieth century is the problem of the color-line, -- the relation of the darker to the lighter races of men in Asia and Africa, in America and the islands of the sea.

    W. E. B. Du Bois: The problem of the twentieth century is the problem of the color-line, -- the relation of the darker to the lighter races of men in Asia and Africa, in America and the islands of the sea.
    The Souls of Black Folk ch. 2 (1903)