Quest for Q

From the Prologue:

"There's nothing in here that could possibly be of interest to you. This story, you see, involves a library. An actual stone and mortar one. Books made out of leather and paper. Been in one? Well, you might have seen pictures.

It also involves a murder mystery, a two-level secret code, three odd teenagers, some snarky gargoyles, and several deep philosophical questions. Most likely not your kind of thing. Really, you should feel perfectly free to stop right here."