In 1903 William Edward Burghardt Du Bois wrote in his classic text The Souls of Black Folk: “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.” This thunderous pronouncement served as Du Bois's clarion call for the nation, grappling with tense and volatile relations between blacks and whites, to engage in objective and thorough research on black Americans. Research and propaganda on the color line was to be Du Bois's life's work. Some of his book-length treatments of the color line include The Suppression of the African Slave-Trade to the United States of America, 1638–1870, The Philadelphia Negro, and The Souls of Black Folk. While each of these books, in addition to the many articles he wrote on the subject, are considered classic works in the area of race, Du Bois's most impressive and influential research on the color line, arguably, consists of the investigations he spearheaded as the director of research at Atlanta University between 1897 and 1914.