Frankly, this is one of those questions that looks straightforward but obscures so much; the process of gathering info on Micheaux has been slow but steady, and earlier sources are now corrected by more recent discoveries. Anyway, start with the books by Thomas Cripps (BLACK FILM AS GENRE, SLOW FADE TO BLACK), and move on to Manthia Diawara's anthology BLACK AMERICAN CINEMA (essays by Cripps, Jane Gaines, and Ron Green), but perhaps most importantly contact and support the Oscar Micheaux newsletter published at Duke by Jane Gaines and Charlene Register. The latest issue has a list of the availabile films by Micheaux on 35mm, 16mm, and video which I put together. It also has a review of a recent documentary on Micheaux and regularly reports on early black film.