I like Managing 12 Volts by Barre. After reading it a couple of times I was able to figure out my electical needs and the solar and generator needed to stay out for a couple of months at a time.
If you are a Desert Southwest boondocker I this Desert Solitaire-A Season in the Wilderness by Edward Abbey is something that should be in your library. Rumor has it Abbey was buried out in the Cabeza Prieta near Ajo, Az.
As bound books - all your manuals, of course. But otherwise, "Back to Basics". Stranded on a desert isle or broke down on the side of the road, that's still my pick. Modern urban dweller or Daniel Boone woodsmen, it doesn't matter. Still best to know how the most basic life-sustaining things function and may be fabricated when need be. Most anything else, you can get online easily.
The only fiction I spotted on my shelf was "Atlas Shrugged" - and that one's only about as fictional as you choose to live it, I guess.
My RV Library:
Bible (etc.)
Road Trip USA - Jensen (has a ton of bookmarks sticking out of it and I love reading it & planning/dreaming)
Home Sweet Motorhome - Maxwell
The Open Road Cookbook - Lund
10 Minute Tech - the latest one, I love reading them
The Lord of the Rings - Tolkien
Fodor's Great American Drives of the West
My Trailer Life campground guide lives in the truck, it's too heavy for the trailer