Card Catalogs, Dewey Decimal and Arranging Your Bookshelves

The alphabet sometimes served as a key for retrieving volumes. In the tenth century, for instance, the Grand Vizier of Persia, Abdul Kassem Ismael, in order not to part with his collection of 117,000 volumes when travelling, had them carried by a caravan of four hundred camels trained to walk in alphabetical order.

--page 193.