The first D&D related books I ever read were the endless quest books. The very first of those I read was the classic Dungeon of Dread as you can see by the picture there by Rose Estes fantasy author extraordinaire (sarcasm there). No it isn't Shakespeare but when I was ten this stuff was high adventure! I owned hundreds of choose your own adventure books and this one was towards the top of my list. I read this thing ragged. Somewhere down the basement book vault I still have it I believe (I was too lazy to look for it before doing this post).
Anyway I would be very remiss if I didn't at least mention the Chronicles of Dragonlance as some of the most influential books of my early childhood. I think I was 11 or 12 when I started reading them and devoured the first I don't know ... what ... 20 or so. After that things fell of the deep end and I looked to other authors. Even there though by the time I was in high school I had stopped reading fantasy and sadly haven't really been back. For a geek who likes fantasy, Warhammer, D&D, etc. I am not very well read. I guess its not a bad thing as when I hit college I majored in history and read hundreds of history books. Then I went on to graduate school and started in on anything related to public administration, health care and general management.
But most of my adult life I've just either been in school working on another degree or during the periods I wasn't in school (and thus experiencing the leisure time reading drought one usually does when they are being required to read metric shit tons ... technical term there) when I did read pulpy adventure stuff it tended to be GW black library stuff. So to this day I've never read Jordan, Brooks, Eddings, Anthony, Goodkind. I of course have read the hobbit, the Lord of the Rings and some random stuff by more obscure authors like Raymond E. Feist (who I turned to after my Dragonlance phase had run its course).