Books in the ordinary case or publishers' binding will, after a short
period of use, show signs of weakness in the joints (where the book and
cover are attached). The paper cracks and both it and the super on the
back of the book loosen and unless immediate attention is given the
stitching breaks and the book must go to the bindery.
This super is a loosely woven cotton cloth which is glued on the backs
of books to help hold the sections together, and extends from the back
of the book to the inside of the cover to help hold the book and cover
together. In the publishers' bindings, this super is usually all that
holds a book in the cover.