Skip to main content
Humanities LibreTexts

3.2: Understanding LC Call (Catalog) Numbers

  • Page ID
    220405
  • \( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \) \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)\(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\) \(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\)\(\newcommand{\AA}{\unicode[.8,0]{x212B}}\)

    In contrast to the DDC, the Library of Congress Classification system (LCC) strives to divide all the world’s knowledge into 21 topical areas and groups them alphanumerically. That is, they first assign a topic area to a letter, and then divide that topic up by numbers. Created by the U.S. Library of Congress to meet the needs of its collection, the first outline of the LCC was released in 1904.[1]

    When learning about the Library of Congress Classification System and rules, you will be tempted to throw your hands up in the air and ask “Why?” Do not do this, for your own sanity. As my colleague Miranda says, “When it comes to the LCC system, we catalogers should not ask questions. We should just do what we are told by the schedules, tables, and rules. If we ask questions, we will quickly lose our sanity.” This is sage advice and should, again, be followed for preservation of your mental health. Writing this section of the textbook was difficult enough. Don’t do mental work that I have already done on your behalf.

    When it comes to the subject headings and captions used, however, we can and must ask questions. Some headings and captions are inherently imbued with the perspectives and biases of past catalogers and librarians. For example, members and aspects of the LGBTQ+ community were previously classed under a variety of diseases and disorders, or “sexual deviations,” until this was rectified in the 2020 edition of the Library of Congress Classification Schedules. Now, these groups are classified under “Sexual practices outside of social norms” and “Sexual minorities,” which are more apt characterizations.

    Library of Congress Classification

    A: General Works

    B: Philosophy, Psychology, Religion

    C: Auxiliary Sciences of History

    D: World History

    E: History of the Americas

    F: History of the Americas

    G: Geography, Anthropology, Recreation

    H: Social Sciences

    J: Political Science

    K: Law

    L: Education

    M: Music

    N: Fine Arts

    P: Language and Literature

    Q: Science

    R: Medicine

    S: Agriculture

    T: Technology

    U: Military Science

    V: Naval Science

    Z: Bibliography, Library Science, Information Resources

    The LCC then adds more letter and numbers after each letter to get more specific within each topic area. Some classes, or “schedules,” use more than one letter while others only use one letter followed by numbers. The main difference between the Dewey Decimal System and the Library of Congress is that this system classifies knowledge according to disciplines rather than subject matter. Therefore, both railroads and the economic and agricultural economy are classified under H (Economy) rather than Technology (T) or Agriculture (S).

    Other numbers in the main subject number deal with the years covered in a particular work. Sometimes, subject and year numbers are so complex that they are divided by periods as well. Thus, there could be three or four Cutter numbers before the space that precedes an author or year Cutter number. The author and/or year number are considered a joint number called the “Item Number.” This is why we say that there is only one Cutter number in the LCC system. Technically, there is only a base number with zero, one, or more decimal places, and a second number made up of a symbol for the author, the title, the format, and/or the year of publication.

    Query \(\PageIndex{1}\)

    Arrangement of Schedule Sections

    There is a particular order that is usually utilized to create and order subdivisions in schedules.

    1. Usually, the first divisions of the subdivision are different forms, such as periodicals and dictionaries.
    2. Second, study and teaching elements, such as textbooks, methodology works, and research publications, are given their own subclasses.
    3. General works about a subject follow in the third subdivision.
    4. Special topics are next, and may have multiple subdivisions.
    5. Subjects that have divisions by geographic area usually have these divisions last in their subclass division schema.

    Forms are the last resort of captions and classifying. Thus, the general label of periodicals and serials should only be used if the work covers a general topic in a serial form. For example, if a serial publication examines Communities, Classes, and Races from a broad perspective then it should have the call number of HT1501. If a work is specifically about cancer and is a periodical, it should be published under the periodical designation regarding cancer, RC251.A1, instead of the General Periodicals and Serials call number for Internal medicine. Cancer, it may be argued, is also a broad category. However, in the context of internal diseases, which is designated by the RC schedule symbol, cancer is only one specific disease.

    The “P” Schedule: Language and Literature

    Literature, which is primarily poetry or prose fiction, is a unique schedule that has necessarily broad geographic and chronological subclasses. The first division of literature in the “P” schedule is by language. Then, the works are divided by time period of the work. These time periods do not designate the life of the author but the time period in which they were creatively active. Then, the geographic location or citizenship of the author is used to further subdivide. If that is not relevant or apparent, the country with which the author was associated throughout their writing career can be used.

    Next, each individual author has their own Cutter number. Some authors have a Cutter number that has been specially assigned by the Library of Congress. Isaac Asimov’s is PS3551.S5. Samuel “Mark Twain” Clemens’ is PS1300-1348, which means that call numbers between 1300 and 1348 are all reserved for various works and groups of works created by Samuel Clemens.

    Nonfiction works by authors should be classified by their topic rather than in the literature section with the fictional works of the author. This may be confusing but can allow users to differentiate between information and entertainment.

    If authors have written works in more than one language, each language will have its own call number for that author.

    If an author does not have a Cutter number, one can be created in the section for that language’s and geographical division’s “Individual authors, A-Z” range. You must pay attention to the schedule, the catalog, and the Names Authority catalog.

    Sometimes, genre, language, or format are a factor in creating a call number. these rules can be adapted and combined with other schemata to create a system that fits the needs of every library. For information about designating format, language, or other facets of an item before the rest of the call number, see the page on Shelving.

    How to Find a Book on the Shelf

    Please watch this video explanation, which demonstrates the different elements of LCC call numbers and how they are ordered on a library shelf:

    This is the transcript of the above video:

    This tutorial will teach you how to read a call number. A call number is found taped to the front or side of a library item to help you locate it on the shelf. This tutorial will show you how to read a call number using this book, “Nursing Management for the Elderly.” Its catalog entry shows the call number in a straight line. Looking at the spine, here is the call number.

    On the book, the call number is divided into four parts. The first part, “RC,” will be found between “RB” and “RD.” The next part, RC954 will be found between RC953 and RC955. The third part of the call number, the letter and number combination, is read as a decimal.

    Any letter and number combinations should be read as decimals. Therefore, in decimals, 0.89 is greater than 0.884.

    Our book is found between this book, “Nursing Care for the Older Adult,” RC954.N884, and this book, “Nursing Older People,” RC954.N893.

    Finally, the last part of the call number is the year that the book was published. At this point, you’ve probably got the book in hand.

    If you have any more questions, contact the librarian by phone, chat, email, or in person at the reference desk.

    Query \(\PageIndex{2}\)

    To explore the Library of Congress Classification System, use the LCC Library Tool that is similar to that created by the LibraryThing for the Dewey Decimal System. This tool is not as intuitive as the other one, but the LCC is not as intuitive as the Dewey Decimal System.


    Parts of this chapter were adapted from a LibreTexts page titled 8.10: Library of Congress Classification (LCC), which was authored, remixed, and/or curated by Walter D. Butler; Aloha Sargent; and Kelsey Smith and is shared under a CC BY 4.0 license.

    Parts of this page were adapted from the Library of Congress Classification Online Training created by Janis L. Young and Daniel N. Joudrey on behalf of the Library of Congress. As an official government publication, this training is in the public domain.


    1. "Library of Congress Classification." (2020, June 23). Librarianship Studies & Information Technology, R23. Retrieved on December 6, 2022, from https://www.librarianshipstudies.com/2017/11/library-of-congress-classification.html.

    3.2: Understanding LC Call (Catalog) Numbers is shared under a CC BY-NC 4.0 license and was authored, remixed, and/or curated by LibreTexts.

    • Was this article helpful?