It's a relatively painless addiction, though, like most addictions it must be fed and that can place a heavy toll on your bank account. You find yourself wandering around used book stores and scanning the book shelves at the local Goodwill for hidden gems, your neck going stiff from reading all the titles sideways. You snatch up even paperback versions of rarer books, just to have a copy, and when you find a beautiful hardcover classic for $15-$25, you justify the purchase as being an investment, even when you realize you just ruined your budget because after all you don't have an "old books that I simply must have" category in it.
Do you smell books? The majority of the time it's a pleasant experience, only marred by mold and cigarette smoke.
Old and new books all have certain smells, and I find that I associate them with past books by their smell. After spending way too many hours with my head on or too close to my textbooks, I can recognize textbook smell. (Side note: I don't think I would have done that if I wasn't homeschooled and my textbooks weren't usually new and clean...yuck) The thin, slick paper and the ink used in textbooks has a certain smell. Rough paper and ink workbooks smell the same as crossword puzzles and coloring books and construction paper. There's the quality paper and ink smell of a well-bound hardcover book, or the basic papery smell that the majority of your paperback 5th-8th grade range books have, the kind you pick up in the childrens' section of Barnes & Noble.
I just pulled an unread old used book off my bookshelf and now I'm struggling to read it instead of burying my nose in it because it smells like books from my childhood, namely Stuart Little, Charlotte's Web and our older set of the Little House On the Prairie books. The book happens to be A Candle For St. Jude and quite honestly I have no idea what it's about, but I recognized the author's name (Rumer Godden) and remembered I'd read some of her books years and years ago, so I picked it up at Goodwill since it was inexpensive but in good condition.
So if you happen to be in a used bookstore here in town and find me totally oblivious to everything but the books that I'm looking at...or possibly smelling...don't worry, I haven't gone crazy. Or at least not any crazier than I already am. ;) I'm merely under the influence of a mildly dangerous drug.