6 Classification and Cataloging

This section covers cataloging very broadly. If you would like more in-depth information about cataloging in libraries, look at our other textbook: Cataloging with MARC, RDA, and Classification Systems.

Without a system of organization, specific information would be impossible to locate in a library. With this in mind, libraries organize and shelf items of the same subject content together. Successful organization systems enable users to find the precise information they are seeking.

Libraries in the United States use two main classification systems:

Dewey Decimal System

Since 1876 the Dewey Decimal Classification has been the basis of library organization. It was created for the purpose of arranging resources in a logical order using Arabic numerals. Knowledge is divided into ten classes, representing traditional academic disciplines. The intent of the ten classes was to cover the universe of knowledge.

Within the ten classes are subclasses which can also be subdivided to gain greater and greater specificity. Example: 700s = The Arts, 740 = Drawing and Decorative Arts, 748 = Glass, and 748.5 = Stained, painted, leaded, mosaic. Further divisions are possible after the decimal for more specificity. See the table below for the ten classes.


  • 000   Generalities
  • 100   Philosophy, parapsychology and occultism, psychology
  • 200   Religion
  • 300   Social Sciences
  • 400   Language
  • 500   Natural sciences and mathematics (Pure science)
  • 600   Technology (Applied Sciences)
  • 700   The Arts
  • 800   Literature and rhetoric
  • 900   Geography, history, and auxiliary disciplines

Library of Congress System

In the early 1900s, the Library of Congress in Washington, D.C. developed the Library of Congress Classification System. The new system was devised because it was felt that the Dewey Decimal Classification System was not flexible enough for the vast collections of the Library of Congress. As time passed, most U.S. research and academic libraries adopted this system.

With this system, knowledge is divided into twenty-one broad categories – labeled A-Z (omitting I, O, W, X, and Y). These categories are then subdivided by adding one or two additional letters and a set of numbers. This alpha-numeric system uses specific subclasses for a variety of the main classes. See the table below for the Library of Congress Classification classes.


  • A   General Works
  • B   Philosophy; Psychology and Religion
  • C   Auxiliary Sciences of History; Civilization
  • D  General and Old World History
  • E   History of North America
  • F   Local U.S. History. Canada. Latin America
  • G   Geography; Maps, Anthropology; Recreation
  • H   Social Sciences; Economics and Sociology
  • J    Political Science
  • K   Law (General)
  • L    Education
  • M   Music
  • N   Fine Arts
  • P    Language and Literature
  • Q   Science
  • R   Medicine
  • S   Agriculture
  • T   Technology
  • U   Military Science
  • V   Naval Science
  • Z   Bibliography, Library Science, Information Resources

Theory, Practice, and Catalog Record Parts

In order to understand the current norms in the field of cataloging, you need to understand some more library history. AACR2, or Anglo-American Cataloging Rules 2, was the accepted set of rules for catalogers for many years. However, it gradually become obsolete in the modern world of digital technology. Therefore, a team of librarians and other information professionals came together to create a new edition. Much like the Constitutional Convention of 1789, they ended up completely straying from that goal and the world is much better for it. The result of their series of meetings was RDA, or Resource Description and Access. It kept the same theoretical framework of AACR2, which was called FRBR, but it updated the terminology and policies to fit the Internet-based library. FRBR stands for Functional Requirements for Bibliographic Records and emphasizes the importance of placing an item in the context of its author, parent works, and other manifestations of the same work. This ensures that inaccurate records are kept at a minimum. RDA helps with ensuring that format, information medium type and other determining aspects of library items are recorded in a manner that is as accurate and standardized as possible.

MARC records were first developed in 1966 by the Library of Congress and have become the standard format for recording and sharing information about a bibliographic item. With the use of content designators (tags, subfield codes, and indicators), information is stored electronically and can be retrieved and interpreted by any other computer that is programmed to read MARC. This creation was the basis for the automation of library bibliographic records. Some of the most important MARC Fields are:

  • 010   LC card number
  • 020   ISBN
  • 050   Library of Congress Classification Number
  • 082   Dewey Decimal Classification Number
  • 100   Personal author main entry
  • 245   Title proper, subtitle, and statement of responsibility
  • 246   Variant form of title
  • 250   Edition statement
  • 260   Publication information
  • 300   Physical description
  • 440   Series
  • 500   General note
  • 505   Contents note
  • 650   Subject heading
  • 700   Personal author added entry

Item Identifiers in Catalog Records

One of the most important aspects of a catalog record is the identifiers of the item and those of related items. Identifiers tell record readers exactly where to find a particular resource. The modern library has four main types of identifiers.

ISBN: International Standard Book Number. This number is created by the publisher of a particular manifestation or expression of a work. ISBNs are not particular to an item, but you should still put them in catalog records so that users can verify what edition or version of an item they are receiving. The serial version of this identifier is ISSN.

URI: Uniform Resource Identifier. This a chain of characters that represent works and items. Originally, only online resources were given URIs. Now, though, some physical items have also been given URIs. A subgroup of URIs is the IRI, or Internationalized Resource Identifier, which allows for non-roman characters in identifiers. URLs are also a form of URI.

The most ubiquitous form of identification in a library record is the item Call Number. Every item in a library has a particular call number, even if it is as simple as BRDSD 1 for the first Broadside in an archival library collection. Different types of libraries have certain standards and procedures for creating a call number. Special libraries, like archives, for example, may only catalog collections of items or boxes of items in a collection rather than individual items. In fact, best practice in this type of library forbids item-by-item cataloging. In general, though, the other types of libraries either use the Dewey Decimal System or Library of Congress Classification System to produce a call number for each item in their collections.

Real-Life Examples

Let us see how libraries apply these concepts and options in real life. In order to understand how to provide effective services, you need some experience on the front end, the user-experience side, of the catalog or discovery service. In fact, unless you are a technical librarian the part of the discovery service you usually use will be the front end.



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