When the Communists came to power in China after World War II they repurposed some things used by the previous government including this pre-stamped postal card which became a library catalog card. The unknown library which used the catalog card classified its books using the Dewey Decimal System. The 508.1 classification is used for natural history. An interesting piece of postal librariana for my collection.
Celebrating 140 Years of the ALA
6 days ago