Well... he was an abolitionist, I know that for sure. Also, although the African-American characters he portrays in his books may speak poorly (then again, ALL his characters speak poorly-- the colloquialism makes the stories realistic), they are very... human. I got the distinct impression that he was trying very hard to show that his African-American characters are people, just people, no different than his white characters. I don't think he was racist; I think he was opposing racism.