Okay, this has been what I have been occupying my time with the past day (Well, more like the past hour) But I made a tutorial on how to make an invisible bookshelf, without ruining a book (because I love my books dearly).
So first, I suppose you need supplies.
You need a metal wall brace (The L-shaped metal thing with three holes) Mine happened to be a 5" X 1", but I suppose bigger would be cool too, (it would be stronger that way, but you don't want it to be longer than the width of the book or else you could see where it sticks out of the wall) just make sure the screws fit and can be flush with the metal. (My screws happened to be 12 X 1-1/2, but they might be different for you.) A stud finder (There's always a joke to that) is very handy, you need to make sure you drill through solid wood or it will tear up the wall and probably fall with the weight of the books. You need a drill, and also some velcro (The kind that can peel and stick to things)
AND OF COURSE A BOOK. I chose Pendragon, Amazing series, I still read it (after all these years!) and the author is a really nice guy! Can't go wrong with those books! (But the book you choose doesn't matter, obviously)