Describes various methods developed to make leather bookbindings in libraries more resistant to atmospheric pollutants and to handling. These include the development of a stable bookbinding leather, some retannages, and the development of protective surface coatings. Impregnation or consolidation are also considered. In addition, some methods for increasing the strength of the leather are discussed, such as the use of polymers, polyurethanes, and acrylics; the polyurethane Lankrothane 1304 proved to be the most useful.