(Weekend posting did not occur as planned.)
The first D&D novel I ever read was the first D&D novel, Quag Keep. I have been an Andre Norton fan since a librarian recommended her books to me when I was 11. I am fairly sure that I read it before I actually played D&D.
I haven't made a practice of reading D&D based novels in general. Mostly I've read whatever has happened to cross my path by chance.