Sewing Repair of Signature in Situ. End-sheets that are part of the signature

This is an unusual construction of a book in that the end-sheet is not one continuous paper. In these early edition Oz books the paste-down is simply the last page of the signature and the fly-leaf is the second to last page. More typically the end-sheet is a folded sheet of paper that is tipped on (glued along a small narrow strip and attached along the inner margin or gutter).  This makes the book harder to repair in general because if the hinge gets broken that means the other half of that page is now loose and may fall out of the book.