Basically, the US military field, medical and engineering manuals should be a staple starting point. Then all the reference books you can find on food production, medicine, engineering, masonry, crafting, electricity, etc. Personally, I prefer to have my books in both print and ebook. eBooks on either a dedicated reader, tablet or netbook. Plus on a flash drive or two. Stripped of DRM, of course.
Oddly enough, the old gentleman who was housesitting my place until I bought it left me a copy of The Encyclopedia of Country Living. Like it thus far. Oddly enough, most of the Foxfire books, I did not care for. Oh, don't get me wrong. Plenty of nuggets of good stuff, but plenty of meh as well. Just be prepared to sift for them.
I also recommend "Mini Farming: Self Sufficiency on 1/4 Acre" and Pocket Ref.
Good rule of thumb. Stay away from survival books, unless they're dedicated to normal wilderness survival type stuff. They're fine for entertainment, nuggets of good information and "sole book in the rucksack". But they will never beat dedicated discipline books for reference material.
