James Baldwin was an amazing man, and his works are well worth reading. He was persistently himself, no matter what forces were ranged against him (and mighty forces were sometimes ranged against him).
I saw the movie a while ago. Having grown up (and read) most of his work, I was expecting few surprises. But that was not the case. The movie had plenty of video that surprised me, probably because video back in the day was temporary. With the exception of a handful of movies and TV series, you either watched it, or missed it. So if you were watching Johnny Carson one night, you missed Dick Cavett. Carson was funny, but Cavett was brilliant, and had brilliant guests. The point is, even if you read all the man's works (and the related works) it is still a very thought provoking documentary that sheds light on a very tumultuous time in American history.