All of these examples of loose, detaching or detached hinges, or tears at the hinge, need to come to the Preservation Unit for repair. The text  block is sagging or pulling away from its cover. Sometimes this is the result of inadequate publisher's binding with especially poor adhesion in the hinge area. This can also be caused when books are dropped on top of each other or against each other in book drops, by improper shelving practices such as shelving books on their fore-edges or leaning books one on another, or rough use.