They are simply a drug.
You'll note I've added "books from my library" to my sidebar. This is a function of Library Thing, a online book-organizing tool that is nothing short of addictive. Pleseantly addictive, to be sure, but still addictive.
You can see my personal catalog here. It isn't all the books I own, but it is virtually all the ones I have here at Carleton, plus a few selected ones I remember possessing at home.