Library classification

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A library book shelf in Hong Kong arranged using the Dewey classification HK Wan Chai Library Inside Bookcase a.jpg
A library book shelf in Hong Kong arranged using the Dewey classification

A library classification is a system of knowledge organization by which library resources are arranged and ordered systematically. Library classifications use a notational system that represents the order of topics in the classification and allows items to be stored in that order. Library classification systems group related materials together, typically arranged as a hierarchical tree structure. A different kind of classification system, called a faceted classification system, is also widely used, which allows the assignment of multiple classifications to an object, enabling the classifications to be ordered in many ways.



Library classification is an aspect of library and information science. It is distinct from scientific classification in that it has as its goal to provide a useful ordering of documents rather than a theoretical organization of knowledge. [1] Although it has the practical purpose of creating a physical ordering of documents, it does generally attempt to adhere to accepted scientific knowledge. [2]

Library classification is distinct from the application of subject headings in that classification organizes knowledge into a systematic order, while subject headings provide access to intellectual materials through vocabulary terms that may or may not be organized as a knowledge system. [3] The characteristics that a bibliographic classification demands for the sake of reaching these purposes are: a useful sequence of subjects at all levels, a concise memorable notation, and a host of techniques and devices of number synthesis [4]


Library classifications were preceded by classifications used by bibliographers such as Conrad Gessner. The earliest library classification schemes organized books in broad subject categories. The earliest known library classification scheme is the Pinakes by Callimachus, a scholar at the Library of Alexandria during the third century BC. During the Renaissance and Reformation era, "Libraries were organized according to the whims or knowledge of individuals in charge." [5] This changed the format in which various materials were classified. Some collections were classified by language and others by how they were printed.

After the printing revolution in the sixteenth century, the increase in available printed materials made such broad classification unworkable, and more granular classifications for library materials had to be developed in the nineteenth century. [6]

In 1627 Gabriel Naudé published a book called Advice on Establishing a Library. At the time, he was working in the private library of President Henri de Mesmes II. Mesmes had around 8,000 printed books and many more Greek, Latin and French written manuscripts. Although it was a private library, scholars with references could access it. The purpose of Advice on Establishing a Library was to identify rules for private book collectors to organize their collections in a more orderly way to increase the collection's usefulness and beauty. Naudé developed a classification system based on seven different classes: theology, medicine, jurisprudence, history, philosophy, mathematics and the humanities. These seven classes would later be increased to twelve. [7] Advice on Establishing a Library was about a private library, but within the same book, Naudé encouraged the idea of public libraries open to all people regardless of their ability to pay for access to the collection. One of the most famous libraries that Naudé helped improve was the Bibliothèque Mazarine in Paris. Naudé spent ten years there as a librarian. Because of Naudé's strong belief in free access to libraries to all people whether they were scholars with references or not, the Bibliothèque Mazarine became the first public library in France around 1644. [8]

Although libraries created order within their collections from as early as the fifth century BC, [6] the Paris Bookseller's classification, developed in 1842 by Jacques Charles Brunet, is generally seen as the first of the modern book classifications. Brunet provided five major classes: theology, jurisprudence, sciences and arts, belles-lettres, and history. [9]


There are many standard systems of library classification in use, and many more have been proposed over the years. However, in general, classification systems can be divided into three types depending on how they are used:

Universal schemes
Covers all subjects, e.g. the Dewey Decimal Classification, Universal Decimal Classification and Library of Congress Classification.
Specific classification schemes
Covers particular subjects or types of materials, e.g. Iconclass, British Catalogue of Music Classification, and Dickinson classification, or the NLM Classification.
National schemes
Specially created for certain countries, e.g. the Swedish library classification system, SAB (Sveriges Allmänna Biblioteksförening).

In terms of functionality, classification systems are often described as:

Subject headings are listed alphabetically, with numbers assigned to each heading in alphabetical order.
Subjects are divided hierarchically, from most general to most specific.
Subjects are divided into mutually exclusive orthogonal facets.

There are few completely enumerative systems or faceted systems; most systems are a blend but favouring one type or the other. The most common classification systems, LCC and DDC, are essentially enumerative, though with some hierarchical and faceted elements (more so for DDC), especially at the broadest and most general level. The first true faceted system was the colon classification of S. R. Ranganathan.

Methods or systems

Classification types denote the classification or categorization according to the form or characteristics or qualities of a classification scheme or schemes. Method and system has similar meaning. Method or methods or system means the classification schemes like Dewey Decimal Classification or Universal Decimal Classification. The types of classification is for identifying and understanding or education or research purposes while classification method means those classification schemes like DDC, UDC.

English language universal classification systems

The most common systems in English-speaking countries are:

Other systems include:

Non-English universal classification systems

Universal classification systems that rely on synthesis (faceted systems)

Newer classification systems tend to use the principle of synthesis (combining codes from different lists to represent the different attributes of a work) heavily, which is comparatively lacking in LC or DDC.

The practice of classifying

Library classification is associated with library (descriptive) cataloging under the rubric of cataloging and classification, sometimes grouped together as technical services. The library professional who engages in the process of cataloging and classifying library materials is called a cataloger or catalog librarian. Library classification systems are one of the two tools used to facilitate subject access. The other consists of alphabetical indexing languages such as Thesauri and Subject Headings systems.

Library classification of a piece of work consists of two steps. Firstly, the "aboutness" of the material is ascertained. Next, a call number (essentially a book's address) based on the classification system in use at the particular library will be assigned to the work using the notation of the system.

It is important to note that unlike subject heading or thesauri where multiple terms can be assigned to the same work, in library classification systems, each work can only be placed in one class. This is due to shelving purposes: A book can have only one physical place. However, in classified catalogs one may have main entries as well as added entries. Most classification systems like the Dewey Decimal Classification (DDC) and Library of Congress Classification also add a cutter number to each work which adds a code for the author of the work.

Classification systems in libraries generally play two roles. Firstly, they facilitate subject access by allowing the user to find out what works or documents the library has on a certain subject. [11] Secondly, they provide a known location for the information source to be located (e.g. where it is shelved).

Until the 19th century, most libraries had closed stacks, so the library classification only served to organize the subject catalog. In the 20th century, libraries opened their stacks to the public and started to shelve library material itself according to some library classification to simplify subject browsing.

Some classification systems are more suitable for aiding subject access, rather than for shelf location. For example, Universal Decimal Classification, which uses a complicated notation of pluses and colons, is more difficult to use for the purpose of shelf arrangement but is more expressive compared to DDC in terms of showing relationships between subjects. Similarly faceted classification schemes are more difficult to use for shelf arrangement, unless the user has knowledge of the citation order.

Depending on the size of the library collection, some libraries might use classification systems solely for one purpose or the other. In extreme cases, a public library with a small collection might just use a classification system for location of resources but might not use a complicated subject classification system. Instead all resources might just be put into a couple of wide classes (travel, crime, magazines etc.). This is known as a "mark and park" classification method, more formally called reader interest classification. [12]

Comparing classification systems

As a result of differences in notation, history, use of enumeration, hierarchy, and facets, classification systems can differ in the following ways:

See also


  1. Bhattacharya, Ganesh; Ranganathan, S R (1974), Wojciechowski, Jerzy A. (ed.), From knowledge classification to library classification, Ottawa Conference on the Conceptual Basis of the Classification of Knowledge, 1971, Munich: Verlag Dokumentation, pp. 119–143
  2. Bliss, Henry Evelyn (1933). The organization of knowledge in libraries. New Yorka: H. W. Wilson.
  3. Lois Mai Chan (September 28, 2007), Cataloging and classification (Cataloging and Classification ed.), The Scarecrow Press, Inc., ISBN   9780810859449, 0810859440
  4. Satija, M P (2015). "Features, Functions and Components of a Library Classification System in the LIS tradition for the e-Environment". Information Science Theory and Practice. 3 (4): 62–77. doi:10.1633/JISTaP.2015.3.4.5.
  5. 1948-, Murray, Stuart (2009). The library : an illustrated history. New York, NY: Skyhorse Pub. ISBN   9781602397064. OCLC   277203534.
  6. 1 2 Shera, Jesse H (1965). Libraries and the organization of knowledge . Hamden, Conn.: Archon Books.
  7. Clarke, Jack A. (1969). "Gabriel Naudé and the Foundations of the Scholarly Library". The Library Quarterly: Information, Community, Policy. 39 (4): 331–343. doi:10.1086/619792. ISSN   0024-2519. JSTOR   4306024.
  8. Boitano, John F. (1996-01-01). "Naudé's Advis Pour Dresser Une Bibliothèque: A Window into the Past". Seventeenth-Century French Studies. 18 (1): 5–19. doi:10.1179/026510696793658584. ISSN   0265-1068.
  9. Sayers, Berwick (1918). An introduction to library classification. New York: H. W. Wilson.
  11. "Subject access points".
  12. Lynch, Sarah N., and Eugene Mulero. "Dewey? At This Library With a Very Different Outlook, They Don't" The New York Times , July 14, 2007.

Related Research Articles

The Bliss bibliographic classification (BC) is a library classification system that was created by Henry E. Bliss (1870–1955) and published in four volumes between 1940 and 1953. Although originally devised in the United States, it was more commonly adopted by British libraries. A second edition of the system (BC2) has been in ongoing development in Britain since 1977.

Colon classification (CC) is a system of library classification developed by S. R. Ranganathan. It was the first ever faceted classification. The first edition was published in 1933. Since then, six more editions have been published. It is especially used in libraries in India.

The Cutter Expansive Classification system is a library classification system devised by Charles Ammi Cutter. The system was the basis for the top categories of the Library of Congress Classification.

Dewey Decimal Classification Library classification system

The Dewey Decimal Classification (DDC), colloquially the Dewey Decimal System, is a proprietary library classification system first published in the United States by Melvil Dewey in 1876. Originally described in a four-page pamphlet, it has been expanded to multiple volumes and revised through 23 major editions, the latest printed in 2011. It is also available in an abridged version suitable for smaller libraries. OCLC, a non-profit cooperative that serves libraries, currently maintains the system and licenses online access to WebDewey, a continuously updated version for catalogers.

The Library of Congress Classification (LCC) is a system of library classification developed by the Library of Congress. It is used by most research and academic libraries in the U.S. and several other countries.

The Universal Decimal Classification (UDC) is a bibliographic and library classification representing the systematic arrangement of all branches of human knowledge organized as a coherent system in which knowledge fields are related and inter-linked. The UDC is an analytico-synthetic and faceted classification system featuring detailed vocabulary and syntax that enables powerful content indexing and information retrieval in large collections. Since 1991, the UDC has been owned and managed by the UDC Consortium, a non-profit international association of publishers with headquarters in The Hague (Netherlands).

This page is a glossary of library and information science.

S. R. Ranganathan Indian mathematician and librarian

Shiyali Ramamrita Ranganathan (S.R.R.) was a mathematician and librarian from India. His most notable contributions to the field were his five laws of library science and the development of the first major faceted classification system, the colon classification. He is considered to be the father of library science, documentation, and information science in India and is widely known throughout the rest of the world for his fundamental thinking in the field. His birthday is observed every year as the National Librarian's Day in India.

A faceted classification is a classification scheme used in organizing knowledge into a systematic order. A faceted classification uses semantic categories, either general or subject-specific, that are combined to create the full classification entry. Many library classification systems use a combination of a fixed, enumerative taxonomy of concepts with subordinate facets that further refine the topic.

This is a conversion chart showing how the Dewey Decimal and Library of Congress Classification systems organize resources by concept, in part for the purpose of assigning call numbers. These two systems account for over 95% of the classification in United States libraries, and are used widely around the world.

Controlled vocabularies provide a way to organize knowledge for subsequent retrieval. They are used in subject indexing schemes, subject headings, thesauri, taxonomies and other knowledge organization systems. Controlled vocabulary schemes mandate the use of predefined, authorised terms that have been preselected by the designers of the schemes, in contrast to natural language vocabularies, which have no such restriction.

The following outline is provided as an overview of and topical guide to library science:

The National Library of Medicine (NLM) classification system is a library indexing system covering the fields of medicine and preclinical basic sciences. The NLM classification is patterned after the Library of Congress (LC) Classification system: alphabetical letters denote broad subject categories which are subdivided by numbers. For example, QW 279 would indicate a book on an aspect of microbiology or immunology.

Knowledge organization (KO), organization of knowledge, organization of information, or information organization is an intellectual discipline concerned with activities such as document description, indexing, and classification that serve to provide systems of representation and order for knowledge and information objects. It addresses the "activities carried out and tools used by people who work in places that accumulate information resources for the use of humankind, both immediately and for posterity. It discusses the processes that are in place to make resources findable, whether someone is searching for a single known item or is browsing through hundreds of resources just hoping to discover something useful. Information organization supports a myriad of information-seeking scenarios." Traditional human-based approaches performed by librarians, archivists, and subject specialists are increasingly challenged by computational algorithmic techniques. KO as a field of study is concerned with the nature and quality of such knowledge organizing processes (KOP) as well as the resulting knowledge organizing systems (KOS).

Faceted search is a technique which involves augmenting traditional search techniques with a faceted navigation system, allowing users to narrow down search results by applying multiple filters based on faceted classification of the items. A faceted classification system classifies each information element along multiple explicit dimensions, called facets, enabling the classifications to be accessed and ordered in multiple ways rather than in a single, pre-determined, taxonomic order.

The British Catalogue of Music Classification is a faceted classification that was commissioned from E. J. Coates by the Council of the British National Bibliography to organize the content of the British Catalogue of Music. The published schedule (1960) was considerably expanded by Patrick Mills of the British Library up until its use was abandoned in 1998. Entries in the catalogue were organized by BCM classmark from the catalogue's inception in 1957 until 1982. From that year the British Catalogue of Music was organized instead by Dewey Decimal Classification number, though BCM classmarks continued to be added to entries up to the 1998 annual cumulation.

In library and information science documents are classified and searched by subject – as well as by other attributes such as author, genre and document type. This makes "subject" a fundamental term in this field. Library and information specialists assign subject labels to documents to make them findable. There are many ways to do this and in general there is not always consensus about which subject should be assigned to a given document. To optimize subject indexing and searching, we need to have a deeper understanding of what a subject is. The question: "what is to be understood by the statement 'document A belongs to subject category X'?" has been debated in the field for more than 100 years.

Dewey-free refers to library classification schemes developed as alternatives to Dewey Decimal Classification (DDC). Dewey-free systems are often based on the BISAC subject headings developed by the Book Industry Study Group, and are typically implemented in libraries with smaller collections. Instead of using numerical notation to indicate a document's shelving location, Dewey-free systems organize documents alphabetically by natural language words. Dewey-free systems have been implemented in both public and school libraries.

The Information Coding Classification (ICC) is a classification system covering almost all extant 6500 knowledge fields. Its conceptualization goes beyond the scope of the well known library classification systems, such as Dewey Decimal Classification (DCC), Universal Decimal Classification (UDC), and Library of Congress Classification (LCC), by extending also to knowledge systems that so far have not afforded to classify literature. ICC actually presents a flexible universal ordering system for both literature and other kinds of information, set out as knowledge fields. From a methodological point of view, ICC differs from the above-mentioned systems along the following three lines:

  1. Its main classes are not based on disciplines but on nine live stages of development, so-called ontical levels.
  2. It breaks them roughly down into hierarchical steps by further nine categories which makes decimal number coding possible.
  3. The contents of a knowledge field is earmarked via a digital position scheme, which makes the first hierarchical step refer to the nine ontical levels, and the second hierarchical step refer to nine functionally ordered form categories.

The Brian Deer Classification System (BDC) is a library classification system used to organize materials in libraries with specialized Indigenous collections. The system was created in the 1970s by Canadian Kahnawake Mohawk librarian A. Brian Deer, and has been adapted for use by a small number of First Nations libraries in Canada.