As some people noted - books expand to overfill the available space. I try to impose some organization, but have failed for the most part, with a couple of exceptions...
I do have a bookshelf of cookbooks and books about food. Actually, I know there are some missing because I only see on of Ruhlman's books and I have the trio. So I need to do more sorting. I'll probably get rid of a few of the more esoteric books, like the one I got when I moved into my Texas house. Not really my style. And it's not like I use cookbooks as anything more than inspiration anyway. (Though baking is a different story and I just realized my Dorie Greenspan baking book isn't there. Must find that.)
In the office/second bedroom there's making books...18+ years of collected creativity, inspiration and instruction. There are pattern books for quilting, sewing, knitting and crocheting. Guide books for spinning, weaving and dyeing. General instruction for all sorts of sewing and needlework from practical clothing to fancy embroidery. Style and design. I just realized there's a book about spices hidden in there, which needs to move to the dining room. Eventually I will sort these so that they cover all six shelves (I know there are more lurking about) and put pretty things in to break up the books. I will probably move another bookshelf into here, but that's a project for a later date and it will probably hold yarn and fabric rather than books.
Some of my other books. I started out with a couple of shelves of children's books, in the top right, and planned a shelf or two of Navy and other military reading. Then I realized that the nautical fiction (yup, every one of the Aubrey-Maturin books (plus a few duplicates), the Hornblower books and the Naval History filled several shelves on their own - and I still have shelves worth of other histories, strategy and random think tank publications about nanotechnology and unmanned vehicles. So, it expanded from three shelves to being scattered all over the house. But at least I know where all the O'Brien books are so I don't have to go hunting to re-read them!
And for those of you who think I'm an overachiever when it comes to putting stuff away - until my excess furniture gets picked up (on Thursday) this place will continue to look like this. In fact, the odds of me doing anything substantive to this space in 12 or so hours between furniture pick-up and my getting underway are nil. Though I may be willing to pull an all-nighter if my essentially compulsive nature takes over. After all, there are still books to be put away, but they're going into those built-ins and right now I can't actually get to them!