The Souls of Black Folk by W.E.B. Du Bois; 1903 (full text)

http://avalon.law.yale.edu/20th_century/dubois_01.asp

Also available as a pdf here from Penn State.

 Dr. Cornel West taught a class at Union Theological Seminary that was built on a close reading of this text along with Du Bois' later Dusk at Dawn.