An attempt to increase # of posts: How are your books organized in the shelf?

Mine used to be arranged according to date of purchase, by genre. But now school books and the leisure-reading books are in two separate shelves and are arranged by spine color.

my books are not arranged in order. some live in bookshelves, some in boxes, others under my bed. but when i need something, i know where it's at.

My books are split into school books and 'for pleasure' books. The 'for pleasure' books are split into fiction and nonfiction. Within each category the books are alphabetized by author, then alphabetized by series, then alphabetized by title. I also have keep books that I want to give away in a separate place.

Yes, I realize that is mildly obsessive.

I need to re-organize my books, as it's been a year since I last worked on my shelves. I organize my books according to different categorization schemes. I really feel like I should settle on one overall system rather than this faux organization that I do.

For example:

While I have a lot of SF, the ones that are part of space opera series like the novels of Alastair Reynolds and Iain M. Banks are in one place, along with the fantasy series of novels by China Mieville.

Sharing one shelf are some writers from different genres whose works I find inspiring: Cornell Woolrich, Ramsey Campbell, T.E.D. Klein, and M. John Harrison.

I have a shelf or two for my "valuable" books: usually small-press titles that cost me a pretty penny and/or signed books.

Etc.

Mine are currently arranged by size. In an attempt to keep as many of them as I can out of the basement and so that I can have as many as possible near me, I have crammed as many as possible into the shelves in my office loft. In order to get more on the shelves they are shelved on their sides by size (no particular order). I’m hoping that if we move soon, I’ll be able to have all my shelves in an upstairs area. When that happens, I’m planning on trying to make sections and alphabetize.