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Chapter 16. National Library of Medicine Classification and Other Modern Classification Schemes

Chapter Outline

  • Introduction

  • National Library of Medicine Classification

  • Other Modern Library Classification Systems

Key Takeaways

An overview of select other classification schemas used for the classification of library collections is covered in this chapter.


The National Library of Medicine (NLM) classification system is a domain-specific classification. Its scope is medicine and preclinical sciences. It is designed to be used with the Medical Subject Headings (MeSH) but also integrates well with the Library of Congress Classification for academic and research libraries that want to use both. Its notation is compatible with LCC's notation, using vacant LCC classes and subclasses. NLM classification contains eight subclasses for the preclinical sciences in QS through QZ, and class W contains twenty-seven subclasses within medicine and related subjects.

NLM advantages

NLM Classification advantages include: (1) currency in the arrangement of medical material and in terminology; (2) compatibility in terminology with Medical Subject Headings;1 (3) compatibility in notation with LCC; (4) the presence of NLM call numbers in both the NLM Web catalog of all types of materials; and (5) the presence of both NLM class numbers and LCC class numbers on most, if not all, LC MARC records for materials in health sciences.


The Universal Decimal Classification is an adaptation and expansion of the Dewey Decimal Classification (DDC). UDC is continually reviewed, revised, corrected, and extended by the UDC Editorial Team. New and amended schedules are released annually. 

UDC follows the basic outline of the Dewey system in the majority of its main classes and major subdivisions but with extensive expansion in order to meet the needs of a system intended to serve as an indexing tool for a universal bibliography. In addition, it has made attempts to remove all national biases. UDC is more synthetic than DDC because it permits notations from different parts of the scheme to be linked using a colon as the connecting symbol, and the latest revisions are totally faceted.

Colon Classification

Of great historical importance, the Colon Classification (CC) was developed by S. R. Ranganathan, a prominent librarian from India, who is considered by many to be the foremost theorist in the field of classification due to his contributions to the theory of facet analysis and synthesis.

CC is a faceted scheme. Each class is broken down into its basic concepts or elements according to certain characteristics, called facets. In addition to subject subdivisions in each main class, there are certain common subdivisions (called isolates in the CC system) that can be applied throughout the entire scheme. These include form and language isolates.

Notation for the CC is extremely mixed and complex. It combines Arabic numerals, capital and lowercase letters, some Greek letters, brackets, and certain punctuation marks.


The Book Industry Standards and Communications (BISAC) Subject Headings List, also known as the Subject Codes List, was developed and maintained by the Book Industry Study Group (BISG). BISAC is mainly an enumerative and alphabetical system, lacking a facet-analytic approach. The Subject headlining list consists of an alphabetical listing of the major subject headings. Alphanumeric subject codes are given for each specific subheading, consisting of the three letters of the major heading and six numerals. A number of libraries, mostly public libraries in the United States, have initiated efforts to change their organization system for their physical collections and move from Dewey to BISAC.

Chapter References/Notes

  1. National Library of Medicine (U.S.). (2014a, September 8). Medical subject headings. Retrieved from

  2. United States Army Medical Library. (1951). Army medical library classification: Medicine. Pre-clinical sciences: QS-QZ, Medicine and related subjects: W (1st ed.). Washington, DC: Government Printing Office.

  3. National Library of Medicine (U.S.). (1999). National Library of Medicine classification: A scheme for the shelf arrangement of library materials in the field of medicine and its related sciences (5th ed., revised). NIH Publication no. 00-1535. Bethesda, MD: National Library of Medicine.

  4. National Library of Medicine (U.S.). (2014b, April 29). NLM classification. Retrieved from

  5. Cutter, C. A., Jones, K. E., Swanson, P. K., & Swift, E. M. (1969). Cutter-Sanborn three-figure author table (Swanson-Swift revision). Chicopee, MA: H. R. Huntting Company.

  6. National Library of Medicine (U.S.). (2014c, April 29). NLM classification practices: Serial publications. Retrieved from

  7. National Library of Medicine (U.S.). (2014d, April 29). NLM classification practices: Early printed books. Retrieved from

  8. Cutter, C. A. (1891–1893). Expansive classification: Part 1: The first six classifications. Boston, MA: C. A. Cutter.

  9. Mowery, R. L. (1976, Spring). The Cutter classification: Still at work. Library Resources and Technical Services, 20, 154–156.

  10. Cutter, C. A. (1904). Rules for a dictionary catalog (4th ed., rewritten). U. S. Bureau of Education, Special Report on Public Libraries, Part II. Washington, DC: Government Printing Office (p. 13).

  11. McIlwaine, I. C. (2000). The universal decimal classification: A guide to its use. The Hague, Netherlands: UDC Consortium (Chapter 1).

  12. Slavic, A. (2004). UDC translations: A 2004 survey report and bibliography. Extensions and Corrections to the UDC, 26, 58–80.

  13. McIlwaine, I. C. (1990). The work of the system development task force. In A. Gilchrist & D. Strachan (Eds.), The UDC: Essays for a new decade (pp. 19–27). London, UK: Aslib.

  14. UDC Consortium. (2015a). International UDC seminar 2015: Classification and authority control. Retrieved from

  15. UDC Consortium. (2015b). UDC online. Retrieved from

  16. Brown, J. D. (1898). Adjustable classification for libraries, with index. London, UK: Library Supply Company.

  17. Ranganathan, S. R., assisted by M. A. Gopinath. (1967). Prolegomena to library classification (3rd ed.). London, UK: Asia Publishing House.

  18. Ranganathan, S. R. (1963). Colon classification (6th ed., reprinted with amendments). Mumbai, India: Asia Publishing House.

  19. Ranganathan, S. R. (1987). Colon classification (7th ed., revised and edited by M. A. Gopinath). Bangalore, India: Sarada Ranganathan Endowment for Library Science. [cf. Dhyani, P. (1988). Colon classification edition 7—An appraisal. International Classification, 15(1), 13.]

  20. Bliss, H. E. (1977- ). Bliss bibliographic classification (2nd ed., edited by J. Mills & V. Broughton, with the assistance of V. Lang). Boston, MA: Butterworths. [See also Bliss Classification Association. (2013). Bliss bibliographic classification: Schedules (2nd ed., edited by J. Mills & V. Broughton). London, UK: Bowker-Saur, 1970-2000; K.G. Saur, 2001–. Retrieved from bcsched.shtml]

  21. Bliss, H. E. (1939). The organization of knowledge in libraries (2nd ed.). New York, NY: The H. W. Wilson Company (pp. 42– 43).

  22. Mills, J. (1976, Spring). The new Bliss classification. Catalogue and Index, 40(1), 3–6.

  23. Bliss Classification Association. (2011). The Bliss bibliographic classification. Retrieved from

  24. Bliss Classification Association, 2011.

  25. Bliss Classification Association. (2007). The Bliss bibliographic classification: History and description. Retrieved from

  26. Bliss Classification Association, 2011.

  27. BISG. BISAC subject codes FAQ. Retrieved from

  28. BISG. About BISAC. Retrieved from

  29. Martínez-Ávila, Daniel. (2016). BISAC Subject Headings List. Knowledge Organization 43(8), 655–662. Also available in ISKO Encyclopedia of Knowledge Organization, eds. Birger Hjørland and Claudio Gnoli,

  30. BISG. Complete BISAC subject headings list, 2019 Edition. Retrieved from

Additional Readings

Here, you will find readings specific to the contents of this chapter.

You may find more readings about similar topics on the Cataloging and Classification Web Resources page

National Library of Medicine (NLM) Classification

  • Universal Decimal Classification,

  • UDC online. Retrieved from

  • UDC Summary [multilingual]. Retrieved from

  • Slavic, A., and Davies, S. (2017). Facet analysis in UDC: questions of structure, functionality and data formality. In: Proceedings of the International UDC Seminar: Faceted Classification Today: Theory, Technology and End Users, 14-15 September 2017, London, UK, pages 425-435. Edited by A. Slavic and C. Gnoli. Also in Knowledge Organization, 44(6) 

  • Vukadin, A., and Slavic, A. (2014.) Challenges of facet analysis and concept placement in universal classifications: the example of architecture in UDC. In: Knowledge organization in the 21st century: proceedings of the Thirteenth International ISKO Conference, 19-22 May 2014, Krakow, Poland. Edited by W. Babik. Wurzburg: Ergon Verlag, pp. 236-243.

Colon Classification

  • Complete BISAC Subject Headings List, 2022 Edition. Retrieved from

  • Martínez-Ávila, D., San Segundo, R. & Olson, H.A. (2014). The Use of BISAC in Libraries as New Cases of Reader-Interest Classifications. Cataloging & Classification Quarterly, 52:2, 137-155, DOI: 10.1080/01639374.2013.846284

  • Martínez-Ávila, D., an Kipp, Ma. (2014). Implications of the Adoption of BISAC for Classifying Library Collections. Knowledge Organization, 41, 377-392. DOI: 10.5771/0943-7444-2014-5-377. 

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