Gil Scott-Heron, one of rap’s earliest (and unfortunately unknown) pioneers, gets his full due in Black Wax, the 1982 documentary recently reissued on video. Interspliced between performance footage of Scott-Heron…

Melvin Van Peebles was one of the first black directors to challenge the white establishment in his films, which include “Watermelon Man” and “Sweet Sweetback’s Baadasssss Song.” In this documentary,…