How are people storing their books? After reading, I've just been putting them vertically on my shelves (what I consider "normal"), but I've just gone back to start re-reading them and I've found that all the skinnier volumes (10ish+) have all developed an extreme bend due to the spines being thicker and more rigid than the other side of the books (the opening side). Looks like, although they appear to be wedged straight on the shelves when viewed from the front (spines out), the opening sides of the books (at the back of the shelf) aren't rigid enough to support the weight of the books, and they flop to one side or the other and thus develop the bend. Has anyone else noticed this and have any tips for trying to flatten the books out again?