My comments about Berdyaev the other day got me thinking about the kinds of reading material I turn to when I'm in the run-up phase for a project. It's research material, but not the kind you might expect.
First off: when I'm working on a given kind of project, I read pretty much no other fiction of the same kind — assuming I can find anything that even comes close to it in my mind in the first place. Back when I was pounding out Flight of the Vajra, I didn't read other space opera, for several reasons: I didn't want to pick up ideas from those books (some of which wouldn't have belonged in my book in the first place anyway); I'd already read plenty of it in the run-up to working on the book, and had decided that stuff wasn't a model I wanted to emulate anyway, but instead look beyond; and a big part of what I wanted to bring to the material wasn't to be found in most of the rest of SF in the first place.
Second, the research material I scare up for a given project is about 50/50 factual and inspirational. The first half is "hard" stuff: historical research, real-world info about people, places, things, behaviors, etc. The second half, though, is more about the ideas behind something. Hence all of my ingestion of Aung San Suu Kyi and Thomas Merton when working on Vajra — I wanted more of that sort of thing in the book than I did David Drake (or even Heinlein, for that matter). I still think I had a little too much of the business where the way such ideas were included in the book was by simply having people sit around and talk about them — and maybe that's something I only single out for criticism in my own work because it's something I'd single out in others' works as well — but that's a discussion for another, longer essay.
I guess I could label each of these "substance" and "atmosphere". The former is the actual nuts and bolts of the story; the latter is the flavor it has. You can build a chair out of most anything, but a chair built from IKEA prefab is going to have a different aura about it than one hand-carved from mahogany.
I used to think atmosphere amounted to nothing more than genre trappings or setting, but there's some greater alchemy at work there that I haven't fully pinned down yet. But a lot of it does seem to revolve around the sensibilities that inform a given work through its author, based in turn on what he's been steeping himself in.
Hard as it is to say this without sounding snobbish, I think that's part of why I actually don't read a lot of SF or fantasy when I want to write those very things. I've already spent a good deal of time marinated in that material — enough, I think, to know where it limits its habitually for the sake of the audience that self-selects for it. The things I most want to do lie, if only in part, outside that circle.