Seven Card Stud for Advanced Players by David Sklansky and High-Low Poker for Advanced Players by Ray Zee should give you a good leg up on stud, stud 8, and Omaha 8.
I'm in the middle of reading A Poker Player's Guide to Mixed Games by Ken Lo, and it looks good so far and covers a lot of games not addressed in other literature, but I hesitate to specifically recommend it without having finished it yet.
Also notable are Super System and Super System 2. Though I don't consider either book the bible of any particular game, they're both good quick-and-dirty primers for several variants.