For those who are reading, the library is probably about 40% Fereldan history, 20% other history, 20% literature, 10% natural sciences, 5% religion, and 5% random stuff. It started out being organized by subject, but the servants borrow books at random and don't always put them back where they found them. About once a year, he goes through and sorts it all, but it's been a while, and it's a bit of a jumble.
There wouldn't be any books of elven or arcane lore because those books are very rare and well beyond his means, but there's a fairly good chance of finding anything else. Eventually, your character will find whatever you think it's useful or amusing for them to find, within those parameters.