I originally thought I could scan in the spines of books from my bookshelves, then place them into the illustrated bookshelves in the design as above. This quickly proved impossible: picture books were way too skinny, I would have needed hundreds to fill the shelves and it was way to time consuming.
Back in the studio, I took individual rows of books, cut them out in Photoshop, then used the 'distort' feature to angle them, so each row of books exactly fitted the crazy perspective of the shelves in the illustration:
Job done (phew!).