"Got back outside and take the little stairwell just to the left stairs coming up here."
I did what he said and ended up in an underground library that scream perfect library ambience: floor to ceiling books bound in leather with gilt lettering, shining brass lamps with green glass shades, reading tables polished to a high shine, and deep, comfy club chairs. The first floor was dedicated to fantasy novels. A man and a woman were reading there and greeted me like an old friend when I entered.
The librarian guided me to the bathroom, which was on the other side of a walkway, overlooking the floors below. "The books on the next floor down deal with fluid science; below that social history; and on the last floor are the convex books."
Sadly I didn't get to see the convex books.