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TSD / Cataloging and Metadata Management: Fundamentals of the NLM® Classification

General Principles

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General Principles


  • The class number chosen should represent, as nearly as possible the primary subject(s) of the material being cataloged, as modified by a topical subheading when appropriate, or, in some cases, by the form or type of material being cataloged

  • Use the most specific number available

  • Use a broader number if:
    • No specific number is available
    • The work deals with several subjects that, taken together, constitute a major part of a larger subject

  • Where more than one primary subject is discussed, choose the class number using the following guidelines:
    • Follow the general principles as covered in this module (e.g., NLM vs. LC classification)
    • Check for special instructions in the schedules
    • If no subject is dominant, class under the first one mentioned in the work being cataloged


Last Reviewed: April 16, 2021