Dragonhide description:
"HP/inch 10 (hide of a dragon is typically between 1/2 inch and 1 inch thick).
Hardness 10
Cost Dragonhide armor costs twice as much as masterwork armor of the same type, but it takes no longer to make than ordinary armor of that type (double all Craft results). If the armor or shield is later given the ability to protect the wearer against that energy type, the cost to add such protection is reduced by 25%." It also includes, "If the dragonhide comes from a dragon that had immunity to an energy type, the armor is also immune to that energy type, although this does not confer any protection to the wearer."
So yeah, you want to make the actual PAPER resistant you have to enchant it. Alternative materials for the actual pages were written-up by a third-party group but are on the PFSRD. Maybe your spellbook is made entirely of bronze and weighs so much you need a donkey to carry it.
Enchanting a spellbook with fire resistance for itself would presumably be the same as a ring of fire resistance (I am just assuming this is about fire) less 30-50% (I'd say 50 but DM's call) because it affects your item instead of you and maybe stick a use-activated Quench spell effect once per day that goes off whenever fire touches it.
Finally I made a homebrew magic item a while back (somehwere in the homebrew forum) that was essentially a Blessed Book except its "pages" were a holographic interface projected by a fist-sized magic ball made of adamantine. It cost 15k gold, more if you got the version which could generate Major Image effects on command, and the artifact version could Fly, was filled with every possible spell, but was intelligent and would only share the knowledge if you proved yourself worthy.
