Dust jacket
Also called Jacket, dust wrapper
A removable printed paper wrapper that goes around a book’s cover and folds inside it with two flaps. It is found mostly on hardbacks.
In practice
Its size depends on the book’s true thickness, so wait for the blank dummy before fixing the spine width. Unlaminated coated paper tends to crack white along the folds and scuff at the edges; lamination protects what will be handled in bookshops. Putting a jacket on every copy is a separate operation, and the quote should show it.