Why are the books organized by size?
The collection is divided into sections like “quarto” (books over 12 inches tall) and “stacks” (books under 12 inches tall) to make maximum use of shelving space; i.e. all the smaller (stacks) books are grouped with a uniform shelving height. This also allows for large books like “folios” (books over 15 inches tall) to lay flat on special larger shelves.