Air Force Aces: Background Information (AFP 70-3)

wraps : The paper covering on the outside of a paperback.

tight : Used to mean that the binding of a book has not been overly loosened by frequent use.

4to : Or quarto. A term used generally to describe the approximate size of a book, a book that is about 10" to 12" tall and roughly squarish in shape. The term is based on the size of paper traditionally used by book printers which has been folded and cut into 16 pages.