In one work, this thinker analyzed Helen Boardman’s three dominant theses about a certain historical period found in textbooks and described a nation as “ashamed” in the section “The Propaganda of History.” That book by this thinker analyzes the “promised land” of the white laborer and begins with the sections “The Black Worker” and “The White Worker.” One work by this thinker was praised for (-5[1])its criticism of the Dunning School in a book by Eric (*) Foner; that book (10[1])was “Black Reconstruction.” Another work by this thinker (10[1])includes many spirituals in “The Sorrow Songs” and begins with the essay “Of our spiritual strivings.” That book by this thinker claims the problem of the twentieth century is the “color line.” This man worked on the Encyclopedia Africana after emigrating to Ghana. For 10 points, name this American thinker and activist who wrote “The Souls of Black Folk.” ■END■ (10[1])