While I was working on my first book,
Jessica Z., I developed a belief that, when I'm writing fiction, I shouldn't read fiction for fear that another author's voice could somehow creep into my own, rendering me unable to work (or worse, render me incapable of creating original thoughts). It's a superstition, really, and a stupid one at that, but superstitions are powerful things. I went with it, and the rule has stuck. Interestingly, prior to making this rule for myself, I drafted a novel that I was not able to sell. Coincidence? I think not!
There is no restriction on other sorts of books, though, so I tend to devour nonfiction during my projects. During the writing of Jessica Z., I read many books about cooking. Not cookbooks so often, but books about the actual process of cooking, or tales of life in a professional kitchen. (I'd worked for a long time a a line cook in a restaurant here in Jackson, and returning to that world — if even only in my head — was comforting.) Anthony Bourdain's Kitchen Confidential was an oft-read favorite; while people love it (or knock it) for the book's bluster and debauchery, the details are perfect, and the underlying story arc of Bourdain kicking addiction and getting himself together is genuinely moving (and it reads at times like fiction, which pretty much blows the basis of my rule right out of the water. Oh, well). George Orwell's Down and Out in Paris and London is a nice trip back in food service time, as is Emile Zola's The Belly of Paris (which apparently has just come out in a very good new translation). If you've ever wondered what it's like to train to be or work as a professional chef, Michael Ruhlman's trio of books, The Making of a Chef, The Soul of a Chef, and The Reach of a Chef are immensely readable and entirely wonderful. Bill Buford's Heat was great too, doing a good job of reminding me of the visceral terror of stepping into a station in a busy kitchen when you maybe, possibly aren't quite ready to be there.
Writing Two Years, No Rain was another trip entirely, and demanded different sorts of reading. I had some notion as I was putting the story together in my head that part of the book would take place in China, so I got Peter Hessler's incredible pair of books about his experiences in Mainland China teaching English and later as a journalist, River Town and Oracle Bones. (I also read Ha Jin's Waiting and War Trash, but since I wasn't actually writing at the time, there was no violation of the no-fiction stricture.) Once I got into actually composing the book itself, my reading veered off into an entirely different direction: as I'd written one of the supporting characters in Two Years, No Rain as a meteorologist for NASA during the Apollo program, I needed to do a little research for an anecdote he tells about one of the missions. I picked up Andrew Chaikin's encyclopedic A Man on the Moon, which, in addition to being densely packed with information, was entirely enjoyable to read (and re-read). Chris Craft's terrific Failure Is Not an Option reinforces every stereotype you may have had about mission control in the sixties: for good or bad, our early voyages beyond earth were indeed shepherded by a bunch of hard-drinking, chain-smoking, dedicated white guys in skinny ties. The best surprise of all, though, was Michael Collins' eloquent Carrying the Fire, a book filled with humor, intelligence, and honest self reflection. I can't recommend that one enough.
Your tastes may not quite match mine. However, if you want to bore your spouse and friends to tears with minutiae like, say, the lightning strike during the launch of Apollo 12, you now know just where to look.