What sort of book subjects could help in fleshing out a story?

So, tomorrow the local library is having a bag-day sale, where you fill a paper bag up with used books, and pay per bag instead of per book. I've been to these sorts of things before and the books tend to be pretty random, so usually I just go there and pick whatever looks interesting.

This time though, I'm trying to be more organized and making a list. I'm looking for topics that aren't directly about fiction writing, but can be a major boon in informing what the hell you're doing when researching or writing a story. I've got a list, but I don't want to show up and end up getting only half a bag just because the list is too short. You guys have any ideas?

What are you writing?

I do mostly speculative fiction. Current story is a bit of a Urban Fantasy involving time travel, magical schooling, espionage, fighting monsters, super powers, and alternate dimensions. The one I'm planning for Na No Wri Mo is fantasy or High Fantasy, high magic centered around maps and Ley Lines, some Man Made Gods, an Evil Empire, creatures akin to The Fair Folk, and a protagonist who can't die.

I tend to go a bit everywhere, though, so suggestions related to other genres would be nice too.

Perhaps you can read a little more on myths and stories to expand your knowledge of the species you're dealing with. Don't forget to draw from many regions.

Everything.

EDIT: okay, actually being helpful:

First and foremost, I recommend psychology and sociology for optimum character development.

edited 16th Sep '11 6:11:04 PM by annebeeche

History, especially of less-known times/places. Pay especial attention to what the author's "theory of history" is, and how it affects the focus of the book.

Books with maps. See how the maps are made, what's considered important, how fictional maps differ from real ones.

"How things work" books. Could your characters build a steam engine if they needed to? How about sewer management?