We too have 100 s of books. You can either shelf them by size. That way the child can eilsay put back a book kinda next to the ones of the same size. OR You shelf them by color. This is an easier way for them to put books back. I've got my kids to also put them back just like at school ~ facing one way and binder out. I put all our books in wooden boxes I purchased at an Unfinished Furniture Store. I wanted to buy shelves from somewhere that would always have them, so I could get more at any time.