<P> A chained library is a library where the books are attached to their bookcase by a chain , which is sufficiently long to allow the books to be taken from their shelves and read , but not removed from the library itself . This would prevent theft of the library 's materials . However , it also led to crowding and awkwardness when readers had to stand side by side , each holding a book or clumping so they could share one . The practice was usual for reference libraries ( that is , the vast majority of libraries ) from the Middle Ages to approximately the 18th century . However , since the chaining process was also expensive , it was not used on all books . Only the more valuable books in a collection were chained . This included reference books and large books . </P>
game of thrones why are there chains in the library
prevent theft of the library 's materials