There's some great stuff in THE X FACTORY, by Anthony Petkovich, published in 1997 in the UK by Critical Vision/Headpress. It reads like ancient history now, but is very enjoyable and interesting. Lots on Gregory Dark--interview, on the set of Sex Freaks, etc. Interviews with Nici Sterling, Chasey Lain, John Leslie, Lana Sands, Patrick Collins, Brittany O'Connell, Bruce Seven, Kaitlyn Ashley, Krysti Lynn, Jasmine St. Claire gangbang, etc.

Good stuff, and not endless shit on the same old subject or homogenized pap for the "I Like Jenna!" ADT crowd.

Five to 18 bucks at Amazon:

http://www.amazon.com/gp/offer-listing/0952328879/ref=dp_olp_used?ie=UTF8&condition=used

I thought a new edition was coming out a few years ago, but I never saw it.