This article discusses three types of library systems: library management software tools, library classification systems, and groups of libraries that function as a collective. Read this article for a greater understanding of library systems.

The term library system can either refer to the management tool that keeps track of the libraries materials, the categorization of materials that provides an orderly arrangement in the library, or the collective group of a central library and its branches, digital holdings, and mobile units. This article will provide an overview of all three types of library system.

A Collection of Libraries

A library may stand alone or be part of a network that includes one or more branches, extensions, bookmobiles, and possibly a designated “main library.” Working together as a system may allow libraries to coordinate in a variety of ways, such as:

  • having various branches open while others take a lunch break
  • sharing out the work of a program, such as a preschool story hour, a summer reading program, or a lecture series
  • having an intermediary step in the interlibrary loan process in which patrons borrow from outside their home branch but within the system

The Library Classification Systems

Among the best-known library classification systems are the Dewey Decimal System (DDC) and the Library of Congress classification. These provide a schema for organizing books on similar subjects in a logical order. Based on whichever system is being used, each book and other piece of library material is assigned a call number. This number allows it to be uniquely identified in the library records, shelved in its proper place, and located by the library patron.

  • sharing an online catalog (and its cost)

Library Management System

The library management system used to be comprised of a card catalog that was updated by hand, and a collection of cards that were kept in paper holders glued into a book. The card catalog had several cards for each book, including cards to allow a patron to find the book by its author, title, or subject matter. When a book was taken out, the two cards were stamped: one was replaced in the book to indicate the due date to the patron; the other was kept in the library to indicate that the volume was circulating.

Resorting the card catalog and keeping it up to date, as new acquisitions were made and old materials were removed, was an arduous task. Tasks such as interlibrary loans and putting holds on a book also required a lot of paperwork and oversight. Nevertheless, in small or private collections, cards, a list, or some other print means may still be used to keep track of the contents of a library collection.

But in many libraries, much has changed. Today, the library's collection is likely to be catalogued in a digital database that can be accessed not only within the library, but from anywhere in the world with computer access. Books and other circulating material are all listed. If the individual library is part of a larger library system, the database may cover the entire system. This means of accessing the library's holdings may be referred to as an online public access catalog (OPAC).

In a digital library, the system and the collection are difficult to distinguish. The same tool that helps you find a library holding is likely to also assist you to read it online, download it, or print it.

The means of searching within the OPAC are expanded from what was possible in the card catalog. The following choices are typical:

  • Title
  • Author
  • Journal Title
  • Subject Heading (for Library of Congress of Medical Subject Headings)
  • Call Number
  • Keyword

Keywords can often be linked by using Boolean operators - and, or, not - to combine search terms. Quotation marks can be used to indicate exact phrases. And ? or * can be used as a wildcard to allow the entry of a truncated word when any ending is acceptable, for example, appl* à apply, application, applicable.

Today, the library system fulfills multiple tasks, maintaining the inventory of the library's holdings, tracking circulation, and cataloging materials. In addition, the system will likely keep track of patrons and their unique ID's. At the circulation desk, several of these systems come together as materials are checked out to particular patrons, or checked back in, and removed from the patron's list of borrowed materials. Sophisticated equipment that scans a code in the patrons library card and in each book is often involved.