"Okay, whoa," he says, holding out a hand to say stop.

"I know he can be- uh- difficult, but it's not like that. He'll let you learn whatever. He just likes to know where his books are. They mean a lot to him. He also knows what magic will work for each of us, and what might be dangerous for us to mess with if we're not ready. And, well, there's the whole thing where that house is kind of the only thing he has that's his. Did you know about him?"