I'm sure this has been stated, but the game is in early access. Books, crafting mats, etc will be included in at some point, but right now, the game itself is getting re-configured and tweaked. They've included some letters and lore books that are quest specific, etc, but most lore books are not essential to the game atm, so we'll just have to wait on them. In regards to the goblin camp being basically empty, well, the town has been looted by goblins, what do you expect.
The books were probably burned for camp fire kindling.
Just as a lot of things in the game, be patient. It's EA, so there's going to be a lot missing yet.
