Inventory level. The level of the library is the same as that of the Cultural Bureau. County-level libraries are stock-level, municipal libraries are division-level and provincial libraries are division-level. A library is an institution that collects, sorts out and collects books and materials for people to read and refer to. As early as 3000 BC, libraries appeared. Library has the functions of preserving human cultural heritage, developing information resources and participating in social education.