Floating Bookshelves: If your book lover is prone to piling books up in stacks everywhere, then maybe it's time to get him an appealing storage solution. An invisible bookshelf is an old favorite and can slip in with most decor. 'Sides, who doesn't like some spooky floating books? $14 [Amazon—or make it yourself via Cut Out + Keep]

Photo of DIY version by Cut Out And Keep