This is when I think I could do with either a real librarian or a real librarian's qualification. For the nth time this summer, we are sorting out books and it's taking up all the imaginative, categorising and sorting skills I have. So we aren't getting far.
We've taken books off shelves, packed them in rented crates for several months, unpacked the crates so that we didn't have to pay to have them for longer than necessary, sorted out the books according the space available in the new kitchen, resorted the rest in the garage (which will need re-resorting before the onset of damp), put the chosen books back on shelves, taken them off so that the shelves could be repainted, and now we have a hall full of books that need sorting out yet again and putting back on newly painted shelves.
But how best to sort them? As I'm not up to using the Dewey Decimal System, we have to decide whether to go alphabetically, by matching height, by matching jacket colour (there are some great photos on Flickr of colourful arrangements), by subject, by publisher, by edition, according to weight (don't want the shelves to sag), most used/least used (least used on top and bottom shelves, most used at eye level), stacked vertically, stacked horizontally, stacked vertically and horizontally, making a concave/Golden Gate Bridge design on each shelf, making a convex/hillocky design on each shelf, putting objets d'art (should we happen to have any) between books, not filling/filling every shelf so that we have interesting positive/negative space things going on, slipping in the odd bar of chocolate camouflaged in Penguin/Persephone colours for emergencies, or a mix of each and every system just to keep us on our toes when we need to find a particular book.
Or maybe we just leave them on the floor a little longer.