sorry, but can't solders buy books themselves!
Kind of hard to pop down to the bookstore when you're knee deep in the shit somewhere in the middle of Afghanistan, you know?
Actually I wouldn't know as I've never been out there nor have the inclination to do so. But the question stands, can't soldiers buy books them selves as the entire American army is not deployed in that rather lovely part of the world!
So again, I suggest, instead of potentially wasting your book donations, give it to charity where someone will buy the novel and then said money can go to a good cause - I myself got rid of a load of books a few months ago and gave them to Oxfam.