Books were not only copied to have 2 functional copies, but also to have 1 fresh copy remaining once the older copy is no longer usable. Books are perishable an

Books were not only copied to have 2 functional copies, but also to have 1 fresh copy remaining once the older copy is no longer usable. Books are perishable and the more they are used, the quicker they disintegrate. That in itself is sufficient reason to sacrifice some works to preserve other works.