Back in the day, a library card was essentially a simple paper card that gave you the right to check out books. Today's library cards still serve that purpose, but their physical appearance is much different, as is their level of functionality.

Most libraries now issue plastic library cards that are the same size and shape as your typical credit card. These durable cards feature a variety of elements including the name of the library, graphics or a logo, the cardholder's name, signature and ID number, and sometimes a magnetic stripe or smart chip for added functionality.

Library cards can now be used to not only borrow books and materials, but also to access library databases online. Cardholders can even access library materials remotely from their home computers.

It's also common for libraries to offer special cards that grant access to collection materials in reading rooms and research libraries, as well as online research catalogs.