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Dewey Decimal Classification

The Dewey Decimal Classification (DDC), or Dewey Decimal System, is a proprietary library classification system first published in the United States by Melvil Dewey in 1876.[1] It has been revised and expanded through 23 major editions, the latest issued in 2011, and has grown from a four-page pamphlet in 1876. It is also available in an abridged version suitable for smaller libraries. It is currently maintained by the Online Computer Library Center (OCLC), a non-profit cooperative that serves libraries. OCLC licenses access to an online version for catalogers called WebDewey.

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.[2] 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.[notes 1] The classification system is used in 200,000 libraries in at least 135 countries.[3][4]

The major competing classification system to the Dewey Decimal system is the Library of Congress Classification system created by the U.S. Library of Congress.



Melvil Dewey, the inventor of the Dewey Decimal classification

1873–1885: Early developmentEdit

Melvil Dewey (1851–1931) was an American librarian and self-declared reformer.[5] He was a founding member of the American Library Association and can be credited with the promotion of card systems in libraries and business.[6] He developed the ideas for his library classification system in 1873 while working at Amherst College library. He applied the classification to the books in that library, until in 1876 he had a first version of the classification. In 1876, he published the classification in pamphlet form with the title A Classification and Subject Index for Cataloguing and Arranging the Books and Pamphlets of a Library.[7] He used the pamphlet, published in more than one version during the year, to solicit comments from other librarians. It is not known who received copies or how many commented as only one copy with comments has survived, that of Ernest Cushing Richardson.[8] His classification system was mentioned in an article in the first issue of the Library Journal and in an article by Dewey in the Department of Education publication "Public Libraries in America" in 1876.[9] In March 1876, he applied for, and received copyright on the first edition of the index.[10] The edition was 44 pages in length, with 2,000 index entries, and was printed in 200 copies.[11]

1885–1942: Period of adoptionEdit

The second edition of the Dewey Decimal system, published in 1885 with the title Decimal Classification and Relativ Index for arranging, cataloging, and indexing public and private libraries and for pamflets, clippings, notes, scrap books, index rerums, etc.,[notes 2] comprised 314 pages, with 10,000 index entries. 500 copies were produced.[11] Editions 3–14, published between 1888 and 1942, used a variant of this same title.[12] Dewey modified and expanded his system considerably for the second edition. In an introduction to that edition Dewey states that "nearly 100 persons hav [spelling of "have" per English-language spelling reform, which Dewey championed] contributed criticisms and suggestions".[13]

One of the innovations of the Dewey Decimal system was that of positioning books on the shelves in relation to other books on similar topics. When the system was first introduced, most libraries in the US used fixed positioning: each book was assigned a permanent shelf position based on the book's height and date of acquisition.[14] Library stacks were generally closed to all but the most privileged patrons, so shelf browsing was not considered of importance. The use of the Dewey Decimal system increased during the early 20th century as librarians were convinced of the advantages of relative positioning and of open shelf access for patrons.[14]

New editions were readied as supplies of previously published editions were exhausted, even though some editions provided little change from the previous, as they were primarily needed to fulfill demand.[15] In the next decade, three editions followed closely on: the 3rd (1888), 4th (1891), and 5th (1894). Editions 6 through 11 were published from 1899 to 1922. The 6th edition was published in a record 7,600 copies, although subsequent editions were much lower. During this time, the size of the volume grew, and edition 12 swelled to 1243 pages, an increase of 25% over the previous edition.[16]

In response to the needs of smaller libraries who were finding the expanded classification schedules difficult to use, in 1894, the first abridged edition of the Dewey Decimal system was produced.[14] The abridged edition generally parallels the full edition, and has been developed for most full editions since that date. By popular request, in 1930, the Library of Congress began to print Dewey Classification numbers on nearly all of its cards, thus making the system immediately available to all libraries making use of the Library of Congress card sets.[17]

Dewey's was not the only library classification available, although it was the most complete. Charles Ammi Cutter published the Expansive Classification in 1882, with initial encouragement from Melvil Dewey. Cutter's system was not adopted by many libraries, with one major exception: it was used as the basis for the Library of Congress Classification system.[18]

In 1895, the International Institute of Bibliography, located in Belgium and led by Paul Otlet, contacted Dewey about the possibility of translating the classification into French, and using the classification system for bibliographies (as opposed to its use for books in libraries). This would have required some changes to the classification, which was under copyright. Dewey gave permission for the creation of a version intended for bibliographies, and also for its translation into French. Dewey did not agree, however, to allow the International Institute of Bibliography to later create an English version of the resulting classification, considering that a violation of their agreement, as well as a violation of Dewey's copyright. Shortly after Dewey's death in 1931, however, an agreement was reached between the committee overseeing the development of the Decimal Classification and the developers of the French Classification Decimal. The English version was published as the Universal Decimal Classification and is still in use today.[19]

According to a study done in 1927, the Dewey system was used in the US in approximately 96% of responding public libraries and 89% of the college libraries.[20] After the death of Melvil Dewey in 1931, administration of the classification was under the Decimal Classification Committee of the Lake Placid Club Education Foundation, and the editorial body was the Decimal Classification Editorial Policy Committee with participation of the American Library Association (ALA), Library of Congress, and Forest Press.[17] By the 14th edition in 1942, the Dewey Decimal Classification index was over 1,900 pages in length and was published in two volumes.[21]

1942–present: Forging an identityEdit

1885 - Dewey Decimal Classification

The growth of the classification to date had led to significant criticism from medium and large libraries which were too large to use the abridged edition but found the full classification overwhelming. Dewey had intended issuing the classification in three editions: the library edition, which would be the fullest edition; the bibliographic edition, in English and French, which was to be used for the organization of bibliographies rather than of books on the shelf; and the abridged edition.[22] In 1933, the bibliographic edition became the Universal Decimal Classification, which left the library and abridged versions as the formal Dewey Decimal Classification editions. The 15th edition, edited by Milton Ferguson, implemented the growing concept of the "standard edition", designed for the majority of general libraries but not attempting to satisfy the needs of the very largest or of special libraries.[23] It also reduced the size of the Dewey system by over half, from 1,900 to 700 pages, a revision so radical that Ferguson was removed[by whom?] from the editorship for the next edition. The 16th and 17th editions, under the editorship of the Library of Congress, grew again to two volumes. However, by now, the Dewey Decimal system had established itself as a classification for general libraries, with the Library of Congress Classification having gained acceptance for large research libraries.[24]

The first electronic version of "Dewey" was created in 1993.[25] Hard-copy editions continue to be issued at intervals; the online WebDewey and Abridged WebDewey are updated quarterly.[26]

Administration and publicationEdit

Dewey and a small editorial staff managed the administration of the very early editions. Beginning in 1922, the Lake Placid Club Educational Foundation, a not-for-profit organization founded by Melvil Dewey, managed administrative affairs. The ALA set up a Special Advisory Committee on the Decimal Classification as part of the Cataloging and Classification division of ALA in 1952. The previous Decimal Classification Committee was changed to the Decimal Classification Editorial Policy Committee, with participation of the ALA Division of Cataloging and Classification, and of the Library of Congress.[27][need quotation to verify]

Melvil Dewey edited the first three editions of the classification system and oversaw the revisions of all editions until his death in 1931. May Seymour became editor in 1891 and served until her death in 1921. She was followed by Dorcas Fellows, who was editor until her death in 1938. Constantin J. Mazney edited the 14th edition. Milton Ferguson functioned as editor from 1949 to 1951. The 16th edition in 1958 was edited under an agreement between the Library of Congress and Forest Press, with David Haykin as director.[17] Editions 16-19 were edited by Benjamin A. Custer and the editor of edition 20 was John P. Comaromi. Joan Mitchell was editor until 2013, covering editions 21 to 23.[28] As of 2013 the Editor-in-Chief is Michael Panzer of OCLC.[29]

Dewey himself held copyright in editions 1 to 6 (1876–1919). Copyright in editions 7–10 was held by the publisher, The Library Bureau.[30] On the death of May Seymour, Dewey conveyed the "copyrights and control of all editions" to the Lake Placid Club Educational Foundation, a non-profit chartered in 1922.[31] The Online Computer Library Center (OCLC) of Dublin, Ohio, US, acquired the trademark and copyrights associated with the Dewey Decimal Classification system when it bought Forest Press in 1988. In 2003 the Dewey Decimal Classification came to national[quantify] attention when OCLC sued the Library Hotel for trademark infringement for using the classification system as the hotel theme.[32] The case was settled shortly thereafter.[33]

The OCLC has maintained the classification since 1988, and also publishes new editions of the system. The editorial staff responsible for updates is based partly at the Library of Congress and partly at OCLC. Their work is reviewed by the Decimal Classification Editorial Policy Committee, a ten-member international board which meets twice each year. The four-volume unabridged edition is published approximately every six years, the most recent edition (DDC 23) in mid-2011.[34] The web edition is updated[by whom?] on an ongoing basis, with changes announced each month.[35] An experimental version of Dewey in RDF is available at[36] This includes access to the top three levels of the classification system in 14 languages.[37]

In addition to the full version, a single-volume abridged edition designed for libraries with 20,000 titles or fewer has been made available since 1895. "Abridged 15" was published in early 2012.[38]

Full edition Publication year Abridged edition Publication year
1st 1876
2nd 1885
3rd 1888
4th 1891
5th 1894 1st 1895
6th 1899
7th 1911
8th 1913 2nd 1915
9th 1915
10th 1919
11th 1922 3rd 1926
12th 1927 4th 1929
13th 1932 5th 1936
14th 1942 6th 1945
15th 1951 7th 1953
16th 1958 8th 1959
17th 1965 9th 1965
18th 1971 10th 1971
19th 1979 11th 1979
20th 1989 12th 1990
21st 1996 13th 1997
22nd 2003 14th 2004
23rd 2011 15th 2012


The Dewey Decimal Classification organizes library materials by discipline or field of study. Main divisions include philosophy, social sciences, science, technology, and history. The scheme is made up of ten classes, each divided into ten divisions, each having ten sections. The system's notation uses Arabic numbers, with three whole numbers making up the main classes and sub-classes and decimals creating further divisions. The classification structure is hierarchical and the notation follows the same hierarchy. Libraries not needing the full level of detail of the classification can trim right-most decimal digits from the class number to obtain a more general classification.[39] For example:

500 Natural sciences and mathematics
510 Mathematics
516 Geometry
516.3 Analytic geometries
516.37 Metric differential geometries
516.375 Finsler Geometry

The classification was originally enumerative, meaning that it listed all of the classes explicitly in the schedules. Over time it added some aspects of a faceted classification scheme, allowing classifiers to construct a number by combining a class number for a topic with an entry from a separate table. Tables cover commonly used elements such as geographical and temporal aspects, language, and bibliographic forms. For example, a class number could be constructed using 330 for economics + .9 for geographic treatment + .04 for Europe to create the class 330.94 European economy. Or one could combine the class 973 for United States + .05 for periodical publications on the topic to arrive at the number 973.05 for periodicals concerning the United States generally. The classification also makes use of mnemonics in some areas, such that the number 5 represents the country Italy in classification numbers like 945 (history of Italy), 450 (Italian language), 195 (Italian philosophy). The combination of faceting and mnemonics makes the classification synthetic in nature, with meaning built into parts of the classification number.[40]

The Dewey Decimal Classification has a number for all subjects, including fiction, although many libraries create a separate fiction section shelved by alphabetical order of the author's surname. Each assigned number consists of two parts: a class number (from the Dewey system) and a book number, which "prevents confusion of different books on the same subject." [7] A common form of the book number is called a Cutter number, which represents the author and distinguishes the book from other books on the same topic.[41]


(From DDC 23[42])

  • 000 – General works, Computer science and Information
  • 100 – Philosophy and psychology
  • 200 – Religion
  • 300 – Social sciences
  • 400 – Language
  • 500 – Pure Science
  • 600 – Technology
  • 700 – Arts & recreation
  • 800 – Literature
  • 900 – History & geography


(From DDC 23[42])

  • T1 Standard Subdivisions
  • T2 Geographic Areas, Historical Periods, Biography
  • T3 Subdivisions for the Arts, for Individual Literatures, for Specific Literary Forms
    • T3A Subdivisions for Works by or about Individual Authors
    • T3B Subdivisions for Works by or about More than One Author
    • T3C Notation to Be Added Where Instructed in Table 3B, 700.4, 791.4, 808–809
  • T4 Subdivisions of Individual Languages and Language Families
  • T5 Ethnic and National Groups
  • T6 Languages

Relative IndexEdit

The Relative Index (or, as Dewey spelled it, "Relativ Index") is an alphabetical index to the classification, for use both by classifiers but also by library users when seeking books by topic. The index was "relative" because the index entries pointed to the class numbers, not to the page numbers of the printed classification schedule. In this way, the Dewey Decimal Classification itself had the same relative positioning as the library shelf and could be used either as an entry point to the classification, by catalogers, or as an index to the Dewey-classed library itself.[43]

Influence and criticismEdit

A library book shelf in Hong Kong classified using the Dewey classification Scheme

Dewey Decimal Classification numbers formed the basis of the Universal Decimal Classification (UDC), which combines the basic Dewey numbers with selected punctuation marks (comma, colon, parentheses, etc.). Adaptations of the system for specific regions outside the English-speaking world include the Korean Decimal Classification, the New Classification Scheme for Chinese Libraries, and the Nippon Decimal Classification (Japanese).[44][45]

Despite its widespread usage, the classification has been criticized for its complexity and limited scope of scheme-adjustment. In particular, the arrangement of subheadings has been described as archaic and as being biased towards an Anglo-American world view.[46][47] In 2007–08, the Maricopa County Library District in Arizona, abandoned the DDC in favor of the Book Industry Standards and Communications (BISAC) system, one that is commonly used by commercial bookstores,[48] in an effort to make their libraries more accessible for patrons. Several other libraries across the United States,[49] and other countries (including Canada and the Netherlands) followed suit.[48] The classification has also been criticized as being a proprietary system licensed by a single entity (OCLC), making it expensive to adopt. However, book classification critic Justin Newlan stands by the Dewey Decimal System, stating newer, more advanced book classification systems "are too confusing to understand for newcomers".[50]

See alsoEdit


  1. ^ Consider as an example a book on the network protocol IPv6. It will be located at 004.62, after general networking books (004.6). The shelf location is thus defined.
  2. ^ Note that the title makes use of Dewey's "reformed spelling" in some areas.


  1. ^ Dewey, Melvil (1876), Classification and Subject Index for Cataloguing and Arranging the Books and Pamphlets of a Library (Project Gutenberg eBook), retrieved 31 July 2012 
  2. ^ Chapter 17 in Joudrey, Daniel N.; Taylor, Arlene G.; Miller, David P. (2015). Introduction to Cataloging and Classification (11th ed.). Santa Barbara, CA: Libraries Unlimited/ABC-CLIO. ISBN 978-1-59884-856-4. 
  3. ^ "Dewey Services". OCLC. 2009. Retrieved November 4, 2009. Offers library users familiarity and consistency of a time-honored classification system used in 200,000 libraries worldwide 
  4. ^ "Countries with libraries that use the DDC". OCLC. 2009. Retrieved November 4, 2009. Libraries in more than 135 countries use the Dewey Decimal Classification (DDC) system to organize their collections for their users. [135 countries are listed.] 
  5. ^ Wiegand, Wayne A. (1996), Irrepressible reformer, Chicago: American Library Association, ISBN 083890680X, 083890680X 
  6. ^ Krajewski, Markus (2011), Paper machines, Cambridge, Mass: MIT Press 
  7. ^ a b Dewey, Melvil (1876), A Classification and Subject Index for Cataloguing and Arranging the Books and Pamphlets of a .., [s.n.], OCLC 78870163 
  8. ^ Comaromi, John P. (1976), The eighteen editions of the Dewey Decimal Classification, Albany, N.Y: Forest Press Division, Lake Placid Education Foundation, p. 43, ISBN 0-910608-17-2 
  9. ^ United States. Bureau of Education. (1876), Public libraries in the United States of America, Washington: Govt. Print. Off., pp. 623–648 
  10. ^ Comaromi (1976), p. 88
  11. ^ a b Comaromi (1976), p. 155
  12. ^ "Dewey decimal classification and relative index (1971)". Internet Archive. Retrieved 14 December 2013. 
  13. ^ Comaromi (1976), p. 171
  14. ^ a b c Chan, Lois Mai (2007), Cataloging and classification (Third ed.), The Scarecrow Press, Inc., p. 321, ISBN 978-0-8108-5944-9, 0810859440 
  15. ^ Comaromi (1976), p. 218
  16. ^ Comaromi (1976), p. 315
  17. ^ a b c "Timeline". OCLC. Retrieved 8 December 2013. 
  18. ^ "Cutter Classification". Forbes Library Subject Guides. Forbes Library. Retrieved 15 December 2013. 
  19. ^ Comaromi (1976), pp. 297-313
  20. ^ Comaromi (1976), p. 321
  21. ^ Comaromi (1976), p. 376
  22. ^ Comaromi (1976), p. 381
  23. ^ Comaromi (1976), p. 345
  24. ^ Chan (2007), pp. 321–323
  25. ^ Trotter, Ross (6 July 1995). "Electronic Dewey: The CD-ROM Version of the Dewey Decimal Classification". Cataloging & Classification Quarterly. 19 (3-4): 213–234. doi:10.1300/J104v19n03_17. Retrieved 15 December 2013. 
  26. ^ Majumder, Apurba Jyoti; Gautam Sarma. "Webdewey: The Dewey Decimal Classification in The Web" (PDF). INFLIBNET Centre, Ahmedabad, Planner 2007 [held at Gauhati University]. Retrieved 15 December 2013. 
  27. ^ Comaromi (1976), p. 416
  28. ^ Chan (2007), pp. 323
  29. ^ Mitchell, Joan (24 January 2013). "Michael Panzer named Editor-in-Chief of the Dewey Decimal Classification system". OCLC Press Release. Retrieved 17 November 2013. 
  30. ^ Dewey, Melvil (1922). Decimal classification and relative index for libraries and personal use .. Lake Placid Club, N.Y: Forest Press. p. 2. OCLC 1367992. 
  31. ^ Comaromi (1976), p. 286
  32. ^ Luo, Michael (September 23, 2003). "Where Did Dewey File Those Law Books?". The New York Times. Retrieved 17 November 2013. 
  33. ^ "OCLC and The Library Hotel settle trademark complaint". Library Technology Guides. October 24, 2003. 
  34. ^ "Latest versions". OCLC. Retrieved 8 December 2013. 
  35. ^ "Updates". OCLC. Retrieved 8 December 2013. 
  36. ^ "Dewey Web Services". OCLC. Retrieved 8 December 2013. 
  37. ^ "Dewey Decimal Classification/Linked Data". OCLC. Retrieved 8 December 2013. 
  38. ^ "Abridged". OCLC. 2012. Retrieved 23 January 2013. 
  39. ^ Chan (2007), pp. 326–331
  40. ^ Chan (2007), p. 331
  41. ^ Chan (2007), p. 333-362
  42. ^ a b OCLC. "Introduction to the Dewey Decimal Classification". Retrieved 8 December 2013. 
  43. ^ United States. Office of Education. (1876), Public libraries in the United States of America, Washington: Govt. print. off., p. 628 
  44. ^ "A Brief Introduction to the Dewey Decimal Classification". OCLC. Retrieved 16 November 2013. 
  45. ^ Taylor, Insup; Wang Guizhi. "Library Systems in East Asia". McLuhan Studies. Retrieved 16 November 2013. 
  46. ^ Kaplan, Tali Balas. "Done with Dewey". ALSC. Retrieved 15 December 2013. 
  47. ^ Fandino, Marta (2008). "UDC or DDC: a note about the suitable choice for the National Library of Liechtenstein" (PDF). Extensions and Corrections to the UDC. Retrieved 15 December 2013. 
  48. ^ a b Clarke, Rachel Ivy (May 7, 2013). "Picturing Classification The Evolution and Use of Alternative Classification in Dutch Public Libraries". Public Libraries Online. Retrieved 15 December 2013. 
  49. ^ Fister, Barbara (October 1, 2009). "In the search for better browsability, librarians are putting Dewey in a different class". The Library Journal. Retrieved 9 February 2014. 
  50. ^ McCarthy, Laena (January 2009). "New Classification System for Public Libraries?". The Public Library Association Blog. Retrieved 15 December 2013. 

External linksEdit