“When I was twelve I spent an entire summer coming up with my own tables of classification based on subject matter. I’ve had to expand the system several times since then.” He glanced around. “Luckily one can just keep adding more numbers. An alphabetisation charm is—well, more complicated than you’d think, the notation takes up half a page. But it’s been designed. It’s easy to implement. It’s just not sensible for a reference library. Where did you study?”

