The number marked on the item itself matches the number in the library catalog record. The call number is used as a way to locate any particular book in the library, and also allows books with similar subjects to be grouped together.
Look at one section of the call number at a time and find the area of shelves with matching numbers.
Start with the signs on the ends of rows. Within the row, look at the call numbers on other books to find the right shelves.
Keep matching as the call number becomes more and more specific. Examples are given below and there is a link to a tutorial.
Oversize books are placed on the bottom shelf. Some areas that are heavily used tend to get out of order. Scan nearby shelves for your title if it is not exactly where it belongs.
If you do not find a book that is listed in the library catalog as “not checked out,” or if you find that you are frustrated by the process, get help from the Reference desk.
Library of Congress (LC) call numbers are used in the main book collection and the Reference collection. Most academic libraries have adopted the classification system developed by the Library of Congress. The Dewey Decimal system is used in most public libraries and many school libraries. Both systems allow adding more call numbers “between” other numbers. Advantages of the LC system are that large numbers of books may be entered in a specific subject area and the numbers on one line do not get as long.
Example 1: QL696.P2438 E27 2003 is the call number of the book Warblers of the Great Lakes Region and Eastern North America, by Chris G. Earley.
| QL | Letters: Identify the major classification group, zoology.
Note: Q alone, general science, is before QA. |
| 696 | First number: Identifies the subject grouping.
The number of digits is important—QL63 is several shelves earlier. Note: If there is a decimal point, the numbers follow the nearest whole number—QL698.3 comes after QL698. |
| .P2438 | Letter/Number group: Identifies a subject subgroup.
This number is treated as a decimal, one position at a time—QL696 .P2438 comes before QL696.P246. |
| E27 | Second Letter/ Number group: The first letter of the author’s last name, and a number that makes it different from others. |
| 2003 | Date of publication
Note: The date of publication is not included on some call numbers of some older materials. |
Example 2: VIDEO BF121 .D57 2001 Tape 9 is the call number of the video Discovering Psychology: Remembering and Forgetting, from WGBH in Boston.
| VIDEO | Special collection where this is shelved, the start of the call number label on the item.
In the online catalog, the location is Videotapes and the call number begins with the classification letters. Note: Special locations also include Reference, Closed Stacks, Marine Collections, Maps, and others. |
| BF | Letters: Identify the major classification group, psychology. |
| 121 | First number: Identifies the subject grouping. |
| .D57 | Letter/Number group: The first letter of the title, because there is no author, and a number that makes it different from others.
This call number does not include a second Letter/Number unit because the subject area is not divided into subgroups. |
| 2001 | Date of publication |
| Tape 9 | Identifies the specific item in a set, added to the call number.
The record has a note Library has: Tapes 1-26. Titles of the tapes are in the Table of Contents, available online for newer materials. Note: Other designations for parts of a set may be added to call numbers, such as v. 6, pt. 3, No. 101, etc. |
Example 3: Books in order on the shelf (from Understanding Call Numbers at Honolulu Community College)
Another explanation of LC call numbers with visual examples: How to Read Call Numbers, from the University of Arizona.
For an interactive site and a chance to check your understanding, try the SatchLCall Tutorial from the University of Pittsburgh.
It may take a few moments to load.
For additional detail, go to Library of Congress Online Catalog
- A: GENERAL WORKS
- B: PHILOSOPHY. PSYCHOLOGY. RELIGION
- C: AUXILIARY SCIENCES OF HISTORY
- D: HISTORY (GENERAL) AND HISTORY OF EUROPE
- E: HISTORY: AMERICA
- F: HISTORY: AMERICA
- G: GEOGRAPHY. ANTHROPOLOGY. RECREATION
- H: SOCIAL SCIENCES
- J: POLITICAL SCIENCE
- K: LAW
- L: EDUCATION
- M: MUSIC AND BOOKS ON 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 (GENERAL)
The Jim Dan Hill Library is a U.S. Government Depository Library, meaning it has an agreement to accept and make available a substantial number of federal government documents.
- The call numbers on U.S. government documents are from the Superintendent of Documents Classification system (Sudoc).
- Although the numbers may look intimidating, the principle is the same as Library of Congress call numbers: match the number in the record to the section of the shelf, and keep matching as the number becomes more specific. Take each portion of the call number in turn, from right to left.
- The first letter of the Sudoc number corresponds to the agency that published the document. Some examples:
- A Agriculture Department
- HH Health and Human Services
- SI Smithsonian Institution
- More about the system can be found in An Explanation of the Superintendent of Documents Classification System from the Library of Congress.
- The Reference Librarians will assist you in finding Government Documents if needed.
Wisconsin state publications are also arranged by agencies, using the Wisconsin State Document Classification System (WIDOCS) developed by the
State Historical Society of Wisconsin Library.
As with the other call number systems, follow the sections of the number from the most general to the most specific.
Local numbers have a lower-case "x" at the end of the call number.
For more information see:
Guide to Wisconsin State Agencies and their Call Numbers.
