Ralph Bunche, PhD has been discussed on GC over the years.
Among his many scholastic, civil rights, and diplomat achievements, he was the first person of color anywhere in the world to receive a Nobel Peace Prize (in 1950).
http://nobelprize.org/nobel_prizes/p...unche-bio.html
http://www.ralphbunche.com/
ETA: The book "Ralph Bunche: Model Negro or American Other" can be found on Google books. It includes an interesting tidbit about how Bunche turned in his Kappa pledge pin, once he enrolled at UCLA, because he saw no need for separate fraternal orgs at integrated schools.