The purpose of commercial binding is to extend "the useful life of worn and damaged hardcover books as well as periodicals, paperback books, pamphlets, music scores and parts, dissertations and theses, spiral- and comb-bound leaves, and other printed materials that benefit from the protection of hard covers" (Guide to the ANSI/NISO/LBI Library Binding Standard, p. 1).
At the UW Libraries, Preservation Services staff prepare about 14,000 volumes a year for commercial binding. Of the titles bound, approximately 65% are journals and 35% are books. Due to budget constraints, commercial binding has typically concentrated on binding unbound journals (like Time Magazine and Journal of American History) and damaged books (mostly rebinds and recases).
Binding is an economical form of preventive care that helps books survive heavy library use, provides support for materials that are not easily shelved without damage, and facilitates collection maintenance. In addition, binding thin materials (like journal issues) together makes it easier for library users to locate them -- title and call number are clearly marked on the spine. Library binding uses materials and methods to make sure the book lasts as long as possible and is easily used by readers (the book lies flat when open for reading and copying, for example). For more information on commercial binding, see these web resources.