I wish I could do it--it's so pretty!! But even now that I've gotten rid of 75% of my books (I was a lit major and a law student, and book-worm on top of it), I still couldn't! I only have two little bookshelves of books. But even still I put them in a loose arrangement by subject, authors, series.
My current system is actually pretty loosey-goosey considering: I grew up in a house where my dad had THOUSANDS of paperbacks in our library. (The others were somewhere else in the house.) It was brick and board shelves from floor to ceiling all around the perimeter of the (large) room plus a whole lot of excess in a walk-in closet. Not counting the kids books. And the books that we kids kept in our own room. ANYWAY---the library was organized by non-fiction, fiction, science-fiction...then author, then title. You really could find anything. It took FOREVER to re-do when we had to empty the shelves when the basement flooded!! He had all three kids alphabetizing all over the floor for days!
Guess I'm just saying--OCD-ness about books is hereditary!

My son is only three and already shows signs when arranging his toys!