Library of Congress Classification in a New Setting

Beyond Shelfmarks

First articulated one hundred years ago, the Library of Congress Classification (LCC) was initially designed and developed to accommodate the Library's own collections. Adopted by many other large American academic and research libraries, whose needs were comparable to LC's own, as well as many general libraries here and abroad, it has become one of the most widely used library classification systems in the world. A factor in these adoptions is probably that Library of Congress cataloging data was made widely available almost from the beginning through the Cataloging Distribution Service, a great convenience to participating libraries because original cataloging and classification have always been labor-intensive. With the advent of the online age and the implementation of the various MARC (MAchine-Readable Cataloging) formats, use of LC cataloging information increased considerably when the Library began distributing its MARC records electronically.

Although in American libraries classification was used primarily as a shelving and location device offering limited subject access through shelf browsing in the manual environment, it has been proven a useful retrieval tool also in online systems that offer sophisticated browsing and searching functions. With the wide availability of MARC records, LC classification information is increasingly being used for this purpose.

The scheme we now know as the Library of Congress Classification came into being in the early twentieth century. It was devised to replace the classification system invented by Thomas Jefferson used by the Library since the early nineteenth century. On the night of August 24, 1814, during the War of 1812, British soldiers set fire to the Capitol, and most of the Library of Congress's collection was destroyed. Some time after, Thomas Jefferson offered to sell Congress his personal library; subsequently, in 1815, the Congress voted $23,950 to purchase Jefferson's personal library of 6,487 books. The books arrived already classified by Jefferson's own system. The Library adopted this system and used it with some modifications until the end of the nineteenth century.

By the 1890s the Library's collection had grown from seven thousand books to nearly one million, and it became obvious that the Jeffersonian system was no longer adequate. The move to the new library building in 1897 made this fact painfully apparent. Contemplation of a new classification scheme for the Library began in the same year, and the decision for its development was made in 1900. A provisional outline was drawn up in 1901. From the beginning, individual schedules of LCC, each of which contains an entire class, a subclass, or a group of subclasses, have been developed and maintained by subject experts, and such experts continue to be responsible, or consulted about the need, for additions and changes. Thus, unlike most other classification systems, LCC was not the product of one mastermind. Indeed, it has been called "a coordinated series of special classes."

Over the years, the schedules have been published as they were completed; by now, many have undergone thorough revision many times, while others took decades to reach initial publication. All have been and continue to be in a state of continuous revision, as the LCC editors strive to keep abreast of the times. Together, with 21 main classes contained in 42 volumes, LCC functions as a comprehensive general library classification scheme.

Until the early 1990s, LCC schedules existed mainly as a print product. Maintenance and revision remained basically manual tasks that proved to be extremely labor-intensive and time-consuming. The conversion of LCC to machine-readable form became imperative. Work began in 1993 and was completed in 1996. For several reasons, the conversion to electronic form – which was done using the USMARC (now called MARC 21) Classification Format -- was an especially important development for LCC. That it greatly improves internal operating efficiency goes without saying. For one, it enables much more efficient production of the print schedules, which continue to be produced. More important, it facilitates revision, not only of whole schedules but also of tables and indexes. Finally and significantly, it makes it possible to develop and issue LCC in electronic formats, such as Classification Plus, a full-text, Windows-based CD-ROM tool updated quarterly, and Classification Web, a web-based tool updated weekly. These tools contain not only LCC but also include the full text of Library of Congress Subject Headings (LCSH), with links between LC subject headings and LCC numbers where appropriate. Furthermore, built into the Classification Web are also links to cataloging databases with sophisticated search options.

LCC enters its second century facing new challenges in a fast-changing intellectual and cultural environment in the electronic information age. Beyond its function as a shelving device for organizing physical collections in libraries, there are three areas in which we see an expanded potential for LCC: first, integrating classification and controlled subject terms for improved information storage and retrieval; second, organizing web resources; and, third, generating domain-specific taxonomies.

LCC and LCSH, with their improved capacities for keeping up to date, and their wide accessibility via the Library's own electronic tools, can become effective systems for organizing the whole spectrum of current literature, wherever, and in whatever form, it resides. A system for merging classification and controlled subject vocabulary – mapping each against the other – has great potential for improving information storage, discovery, and retrieval. This is because classification and subject headings complement each other. A subject heading or descriptor, along with its syndetic apparatus, represents a particular topic treated from all aspects. On the other hand, classification of a topic places it among related topics treated from the same perspective or within the same discipline. Traditionally, each approach has a specific function in information storage and retrieval. Used together, they can improve effectiveness and efficiency both. With Classification Plus and Classification Web, the Library of Congress has already taken steps toward such a system. Implemented in a search vehicle, the gain in discovery and retrieval power would be tremendous. It could be, therefore, that Library of Congress access provisions will have an even wider retrieval role to play in the future than they have had in the past.

In recent decades, we have seen a rapid growth of the Internet; it now contains an enormous store of electronic resources. It became more and more apparent that effective means were needed to organize what it had to offer. Many libraries and research institutions, recognizing the richness and overwhelming quantity of information resources on the Web, have incorporated selected Web resources into their local online systems or portals. They, as well as web resource providers themselves, are increasingly turning to hierarchical or classification-based schemes as means of categorizing and organizing their resources for access. This is a logical development; after all, classification was devised in the beginning as a response to the need for organizing large bodies of material. Existing schemes are candidates for serving as models for organizing Web resources. Where LCC can make a definite contribution, however, is in its detailed and specific provisions, its broad range of coverage, and now its ease of access.

Because it has been developed and maintained by subject specialists, LCC has sometimes been viewed as a scheme lacking an overall coherent and logical structure from a theoretical standpoint. However, from another perspective, this apparent weakness is a source of strength. The specialists responsible for a given area in a classification scheme are in a better position than generalists to keep the schedules for that area in conformance with current notions of how topics within it are either interrelated or related to other areas previously thought to be outside that area's bounds. The result of the "departmentalized" approach of LCC is that individual classes or parts of the scheme—such as the classifications of law, religion, art, and cartographic materials, to name a few—can be adopted as stand-alone, specialized schemes or serve as models for developing such schemes.

Classification modules or mini-classification schemes with special focuses can also be built on the basis of LCC to meet the needs for effectively organizing web resources and digital libraries in specific subject areas (e.g., education, human environmental sciences, mathematics, engineering), industries (e.g., petroleum, manufacturing, entertainment), consumer-oriented topics (automobiles, travel, sports), problems (e.g., environment, aging, juvenile delinquency), as well as the needs of specialized user communities (e.g., special libraries, corporate information centers, personal resource collections). Where more details are needed in a particular situation, the basic structure of LCC can be extended, thus making the specialized scheme interoperable among one another, within the main LCC structure. The availability of tools such as Classification Plus and Classification Web greatly facilitates the creation of these domain-specific taxonomies and specialized subject classifications. With these new vehicles, the Library of Congress Classification, initiated over a century ago, may look forward to another productive century of service, extending its usefulness beyond that of a shelving device to a tool for organizing and providing access to electronic and networked resources.

Lois Mai Chan, Professor, School of Library and Information Science, University of Kentucky,
Lexington, KY, is the author of numerous articles and books on cataloging, classification, and subject indexing, including A Guide to the Library of Congress Classification, Library of Congress Subject Headings: Principles and Application, and Cataloging and Classification: An Introduction, and co-authored Dewey Decimal Classification: A Practical Guide and Thesauri used in Online Databases. In 1989 she received the Margaret Mann Citation for Outstanding Achievement in Cataloging and Classification. Her research interests include classification, controlled vocabulary, authority control, metadata, and retrieval of Web resources.

References:

Chan, Lois Mai. "Exploiting LCSH, LCC, and DDC to Retrieve Networked Resources: Issues and Challenges," in Proceedings of the Bicentennial Conference on Bibliographic Control for the New Millennium: Confronting the Challenges of Networked Resources and the Web, Washington, D.C., November 15-17, 2000, sponsored by the Library of Congress Cataloging Directorate, edited by Ann M. Sandberg-Fox (Washington, DC: Library of Congress, Cataloging Distribution Service, 2001), pp. 159-78.

Chan, Lois Mai. A Guide to the Library of Congress Classification. 5th ed. Englewood, CO: Libraries Unlimited, 1999
LaMontagne, Leo E. American Library Classification with Special Reference to the Library of Congress. Hamden, CT: Shoe String Press, 1961.
Maltby, Arthur. Sayers' Manual of Classification for Librarians. 5th ed. London: Andre Deutsch, 1975.