The first library catalogs were simply lists of the books owned, listed in the order in which they were purchased. This holdings list did not prove to be very user friendly. The next step was to alphabatize the holdings list. This resulted in an index, which many small private libraries still use today.
The limitation of the index, of course, is that every time a new book is added, it needs to be updated. And it is very difficult and expensive to update an index. The next refinement, to address this limitation, was the card catalog. The index was broken into individual citations which were placed on cards. This allowed the easy addition of new materials. The next refinement was to create three cards for each book and then alphabatize one by author, one by title, and one by subject. Thus were created the three card catalog systems familiar to most library users of the past century.
The advent of the computer allowed libraries to return to the whole index. Automation meant that you could search the entire index by any of the terms found therein: title, author, subject, key word, call number, ISBN. Newer computers even allowed the use of boolean logic in searches.
Let's take a look, now at the PAC online catalog.
Please send comments to: Colby Glass, MLIS