Library 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 in 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 multiple ways. The library classification numbers can be considered identifiers for resources but are distinct from the International Standard Book Number (ISBN) or International Standard Serial Number (ISSN) system.

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


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 BCE. 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]

Although libraries created order within their collections from as early as the fifth century B.C.,[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.[7]


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:

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

  • enumerative: subject headings are listed alphabetically, with numbers assigned to each heading in alphabetical order.
  • hierarchical: subjects are divided hierarchically, from most general to most specific.
  • faceted or analytico-synthetic: 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:

  • Harvard-Yenching Classification, an English classification system for Chinese language materials
  • V-LIB 1.2 (2008 Vartavan Library Classification for over 700 fields of knowledge, currently sold under license in the UK by Rosecastle Ltd[8]

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.[9] 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.[10]

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:

  • Type of Notation: Notation can be pure (consisting of only numerals, for example) or mixed (consisting of letters and numerals, or letters, numerals, and other symbols).
  • Expressiveness: This is the degree to which the notation can express relationship between concepts or structure.
  • Whether they support mnemonics: For example, the number 44 in DDC notation often means it concerns some aspect of France. For example, in the Dewey classification 598.0944 concerns "Birds in France", the 09 signifies geographical division, and 44 represents France.
  • Hospitality: The degree to which the system is able to accommodate new subjects.
  • Brevity: The length of the notation to express the same concept.
  • Speed of updates and degree of support: The better classification systems are frequently being reviewed.
  • Consistency
  • Simplicity
  • Usability

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.
  5. ^ 1948-, Murray, Stuart, (2009). The library : an illustrated history. New York, NY: Skyhorse Pub. ISBN 9781602397064. OCLC 277203534.
  6. ^ a b Shera, Jesse H (1965). Libraries and the organization of knowledge. Hamden, Conn.: Archon Books.
  7. ^ Sayers, Berwick (1918). An introduction to library classification. New York: H. W. Wilson.
  8. ^
  9. ^ "Subject access points".
  10. ^ 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.


  • Chan, Lois Mai. (1994) Cataloging and Classification: An Introduction, second ed. New York: McGraw-Hill. ISBN 978-0-07-010506-5, ISBN 978-0-07-113253-4.
Bliss bibliographic classification

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.

Chinese Library Classification

The Chinese Library Classification (CLC; Chinese: 中国图书馆分类法), also known as Classification for Chinese Libraries (CCL), is effectively the national library classification scheme in China. It is used in almost all primary and secondary schools, universities, academic institutions, as well as public libraries. It is also used by publishers to classify all books published in China.

The Book Classification of Chinese Libraries (BCCL) was first published in 1975, under the auspices of China's Administrative Bureau of Cultural Affairs. Its fourth edition (1999) was renamed CLC. In September 2010, the fifth edition was published by National Library of China Publishing House.

CLC has twenty-two top-level categories, and inherits a Marxist orientation from its earlier editions. (For instance, category A is Marxism, Leninism, Maoism & Deng Xiaoping Theory.) It contains a total of 43600 categories, many of which are recent additions, meeting the needs of a rapidly changing nation.

Colon classification

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

Its name "colon classification" comes from the use of colons to separate facets in class numbers. However, many other classification schemes, some of which are completely unrelated, also use colons and other punctuation in various functions.

In CC, facets describe "personality" (the most specific subject), matter, energy, space, and time (PMEST). These facets are generally associated with every item in a library, and so form a reasonably universal sorting system.As an example, the subject "research in the cure of tuberculosis of lungs by x-ray conducted in India in 1950" would be categorized as:

Medicine,Lungs;Tuberculosis:Treatment;X-ray:Research.India'1950This is summarized in a specific call number:


Cutter Expansive Classification

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

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 Decimal Classification introduced the concepts of relative location and relative index which allow new books to be added to a library in their appropriate location based on subject. Libraries previously had given books permanent shelf locations that were related to the order of acquisition rather than topic. The classification's notation makes use of three-digit Arabic numerals for main classes, with fractional decimals allowing expansion for further detail. Using Arabic numerals for symbols, it is flexible to the degree that numbers can be expanded in linear fashion to cover special aspects of general subjects. A library assigns a classification number that unambiguously locates a particular volume in a position relative to other books in the library, on the basis of its subject. The number makes it possible to find any book and to return it to its proper place on the library shelves. The classification system is used in 200,000 libraries in at least 135 countries.

Faceted classification

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.

ISO 12006

ISO 12006 "Building construction - Organization of information about construction works" is an international standard dealing with structuring of information for construction. It is composed of two parts:

ISO 12006-2:2015 "Building construction - Organization of information about construction works - Part 2: Framework for classification of information" more details in:

ISO 12006-3:2007 "Building construction - Organization of information about construction works - Part 3: Framework for object-oriented information" also known as buildingSMART Data Dictionary or International Framework for Dictionaries (IFD) Library.Classification of project stages:

inception/ procurement


outline proposals, programme preparation

scheme detail/ costing

detail design/ costing

production information and bills of quantities preparation

tender action

construction preparation

construction operations on site



Integrated Authority File

The Integrated Authority File (German: Gemeinsame Normdatei; also known as the Universal Authority File) or GND is an international authority file for the organisation of personal names, subject headings and corporate bodies from catalogues. It is used mainly for documentation in libraries and increasingly also by archives and museums. The GND is managed by the German National Library (German: Deutsche Nationalbibliothek; DNB) in cooperation with various regional library networks in German-speaking Europe and other partners. The GND falls under the Creative Commons Zero (CC0) licence.The GND specification provides a hierarchy of high-level entities and sub-classes, useful in library classification, and an approach to unambiguous identification of single elements. It also comprises an ontology intended for knowledge representation in the semantic web, available in the RDF format.The Integrated Authority File became operational in April 2012 and integrates the content of the following authority files, which have since been discontinued:

Name Authority File (German: Personennamendatei; PND)

Corporate Bodies Authority File (German: Gemeinsame Körperschaftsdatei; GKD)

Subject Headings Authority File (German: Schlagwortnormdatei; SWD)

Uniform Title File of the Deutsches Musikarchiv (German: Einheitssachtitel-Datei des Deutschen Musikarchivs; DMA-EST)At the time of its introduction on 5 April 2012, the GND held 9,493,860 files, including 2,650,000 personalised names.


A library is a collection of sources of information and similar resources, made accessible to a defined community for reference or borrowing. It provides physical or digital access to material, and may be a physical building or room, or a virtual space, or both. A library's collection can include books, periodicals, newspapers, manuscripts, films, maps, prints, documents, microform, CDs, cassettes, videotapes, DVDs, Blu-ray Discs, e-books, audiobooks, databases, and other formats. Libraries range in size from a few shelves of books to several million items. In Latin and Greek, the idea of a bookcase is represented by Bibliotheca and Bibliothēkē (Greek: βιβλιοθήκη): derivatives of these mean library in many modern languages, e.g. French bibliothèque.

The first libraries consisted of archives of the earliest form of writing—the clay tablets in cuneiform script discovered in Sumer, some dating back to 2600 BC. Private or personal libraries made up of written books appeared in classical Greece in the 5th century BC. In the 6th century, at the very close of the Classical period, the great libraries of the Mediterranean world remained those of Constantinople and Alexandria.

A library is organized for use and maintained by a public body, an institution, a corporation, or a private individual. Public and institutional collections and services may be intended for use by people who choose not to—or cannot afford to—purchase an extensive collection themselves, who need material no individual can reasonably be expected to have, or who require professional assistance with their research. In addition to providing materials, libraries also provide the services of librarians who are experts at finding and organizing information and at interpreting information needs. Libraries often provide quiet areas for studying, and they also often offer common areas to facilitate group study and collaboration. Libraries often provide public facilities for access to their electronic resources and the Internet.

Modern libraries are increasingly being redefined as places to get unrestricted access to information in many formats and from many sources. They are extending services beyond the physical walls of a building, by providing material accessible by electronic means, and by providing the assistance of librarians in navigating and analyzing very large amounts of information with a variety of digital resources. Libraries are increasingly becoming community hubs where programs are delivered and people engage in lifelong learning. As community centers, libraries are also becoming increasingly important in helping communities mobilize and organize for their rights. The relationship between librarianship and human rights works to ensure that the rights of cultural minorities, immigrants, the homeless, the disabled, LGBTQ community, as well as other marginalized groups are not infringed upon as protected in the Universal Declaration of Human Rights.

Library branch

A library branch, branch library or community library is a library that forms part of a library system but are not located in the same area, building or city, but use the same library classification for their catalogs and are interconnected with all the branches of the system that form part of the systems and to library patrons through a integrated library system.Most of counties of every country have their own library system, for example: London Public Library (Canada) with 16 library branches, Helsinki Metropolitan Area Libraries with 63 libraries, National Library of Venezuela with 685 branches.

Some popular library branches include New York Public Library Main Branch, part of New York Public Library System, and Martin Luther King Jr. Memorial Library, a branch of District of Columbia Public Library System.

Library of Congress Classification

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.LCC should not be confused with LCCN, the system of Library of Congress Control Numbers assigned to all books (and authors), which also defines URLs of their online catalog entries, such as "82006074" and "". The Classification is also distinct from Library of Congress Subject Headings, the system of labels such as "Boarding schools" and "Boarding schools—Fiction" that describe contents systematically. Finally, the classifications may be distinguished from the call numbers assigned to particular copies of books in the collection, such as "PZ7.J684 Wj 1982 FT MEADE Copy 1" where the classification is "PZ7.J684 Wj 1982".The classification was invented by Herbert Putnam in 1897, just before he assumed the librarianship of Congress. With advice from Charles Ammi Cutter, it was influenced by his Cutter Expansive Classification, the Dewey Decimal System, and the Putnam Classification System (developed while Putnam was head librarian at the Minneapolis Public Library). It was designed specifically for the purposes and collection of the Library of Congress to replace the fixed location system developed by Thomas Jefferson. By the time Putnam departed from his post in 1939, all the classes except K (Law) and parts of B (Philosophy and Religion) were well developed.

LCC has been criticized for lacking a sound theoretical basis; many of the classification decisions were driven by the practical needs of that library rather than epistemological considerations. Although it divides subjects into broad categories, it is essentially enumerative in nature. That is, it provides a guide to the books actually in one library's collections, not a classification of the world.

In 2007 The Wall Street Journal reported that in the countries it surveyed most public libraries and small academic libraries used the older Dewey Decimal Classification system.The National Library of Medicine classification system (NLM) uses the initial letters W and QS–QZ, which are not used by LCC. Some libraries use NLM in conjunction with LCC, eschewing LCC's R for Medicine. Others use LCC's QP–QR schedules and include Medicine R.

List of Dewey Decimal classes

The Dewey Decimal Classification (DDC) is structured around ten main classes covering the entire world of knowledge; each main class is further structured into ten hierarchical divisions, each having ten sections of increasing specificity. As a system of library classification the DDC is "arranged by discipline, not subject", so a topic like clothing is classed based on its disciplinary treatment (psychological influence of clothing at 155.95, customs associated with clothing at 391, and fashion design of clothing at 746.92) within the conceptual framework. The list below presents the ten main classes, hundred divisions, and thousand sections.

Medical classification

Medical classification, or medical coding, is the process of transforming descriptions of medical diagnoses and procedures into universal medical code numbers. The diagnoses and procedures are usually taken from a variety of sources within the health care record, such as the transcription of the physician's notes, laboratory results, radiologic results, and other sources.

Diagnosis codes track diseases and other health conditions, inclusive of chronic diseases such as diabetes mellitus and heart disease, and infectious diseases such as norovirus, the flu, and athlete's foot. Procedure codes track interventions performed. These diagnosis and procedure codes are used by health care providers, government health programs, private health insurance companies, workers' compensation carriers, software developers, and others for a variety of applications in medicine, public health and medical informatics, including:

statistical analysis of diseases and therapeutic actions

reimbursement (e.g., to process claims in medical billing based on diagnosis-related groups)

knowledge-based and decision support systems

direct surveillance of epidemic or pandemic outbreaksThere are country specific standards and international classification systems.

Melvil Dewey

Melville Louis Kossuth "Melvil" Dewey (December 10, 1851 – December 26, 1931) was an American librarian and educator, inventor of the Dewey Decimal system of library classification, and a founder of the Lake Placid Club.

New Classification Scheme for Chinese Libraries

The New Classification Scheme for Chinese Libraries is a system of library classification developed by Yung-Hsiang Lai since 1956. It is modified from "A System of Book Classification for Chinese Libraries" of Liu Guojun, which is based on the Dewey Decimal System.

The scheme is developed for Chinese books, and commonly used in Taiwan, Hong Kong and Macau.

Outline of books

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

Book – set of written, printed, illustrated, or blank sheets, made of ink, paper, parchment, or other materials, usually fastened together to hinge at one side.

Swedish library classification system

The Swedish library classification system, (Swedish: Klassifikationssystem för svenska bibliotek), or SAB system (SAB-systemet) is a library classification system for use in many public, school, and research libraries in Sweden. It primarily classifies books but is also used for other media, such as audio and video recordings. The first edition of the system was released in 1921 and was based on the classification that was used in the accession catalogs of the scientific libraries of that time. The abbreviation 'SAB' is for "Sveriges Allmänna Biblioteksförening" (Sweden's public library association). SAB merged with Svenska bibliotekariesamfundet (Swedish librarians' association) to form present day Svensk Biblioteksförening (Swedish library association).

The SAB system is regularly revised to track developments in new subject areas. The committee for classification systems for Swedish libraries — a part of Svensk Biblioteksförening — promulgates changes, corrections, and usage notes. Larger revisions may cause changes to the whole system and a new version of the classification system is published. The latest, eighth revision was started in 2002 and was put in use in autumn 2006.

Both the research libraries (via the National Library of Sweden) and the public libraries decided at the end of 2008 to recommend a transition to the Dewey Decimal system. The research libraries' major reason for transitioning are simplification: large parts of research literature is already classified in this system. For public libraries the concern is to have the same classification system over the entire country. A considerable savings would be enjoyed by both parties by not having to maintain a distinct national classification system.

Universal Decimal Classification

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).

Unlike other library classification schemes that have started their life as national systems, the UDC was conceived and maintained as an international scheme. Its translation in world languages started at the beginning of the 20th century and has since been published in various printed editions in over 40 languages. UDC Summary, an abridged Web version of the scheme is available in over 50 languages. The classification has been modified and extended over the years to cope with increasing output in all areas of human knowledge, and is still under continuous review to take account of new developments.Albeit originally designed as an indexing and retrieval system, due to its logical structure and scalability, UDC has become one of the most widely used knowledge organization systems in libraries, where it is used for either shelf arrangement, content indexing or both. UDC codes can describe any type of document or object to any desired level of detail. These can include textual documents and other media such as films, video and sound recordings, illustrations, maps as well as realia such as museum objects.

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