What does "quarto" mean?

"Quarto" is a call number prefix used to identify oversized books. These larger books are usually shelved separately from the main sequence because it makes much more efficient use of the shelves to store them this way.

If the book that you want is prefixed by "quarto" you need not worry - it will be just as easy to find as any other book. Just look on the floorplan and you will be able to see where the quarto books are kept.