This is another great documentary from Leva FilmWorks. It very much stays on topic, gives lots of good information into how THX:1138 was made from multiple perspectives, and doesn't stray too much into obscure subjects and minutia. While there are appearances by other notable filmmakers, this does not turn into a love fest. If you are a fan of THX, you'll smile quite a few times.
I give it 8.5 out of 10.
If you are really interested in some of the more personal aspects behind the making of THX:1138, be sure to see A Legacy of Filmmakers: The Early Days of American Zoetrope - found on the same bonus DVD as Artifact from the Future in the Directors Cut DVD release of THX:1138.