If you're interested in the convoluted mythology of parts four, five, and six, there's a perfectly good Wiki page on the matter. (avclub.com)
I'm constantly looking up things on wiki for information on certain topics especially sciences like chemistry, biology, and astrology. (gayasianhookup.com)
The pages and pages of wikis for previous entries are now almost unnecessary as you can find a lot of the information within the game, but you'll need to be paying attention if you want to know what your enemy is weak to, or where to find a particular kind of bone. (thesixthaxis.com)