The novelist might very well have 12,000 books (I have about 7,500), but the double sided bookshelf in the picture would need to be between 50 to 100 feet long

The novelist might very well have 12,000 books (I have about 7,500), but the double sided bookshelf in the picture would need to be between 50 to 100 feet long in order to hold that many books.