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Classification Systems & Call Numbers

Learn about: The three major library classification systems, how LC and SuDoc call numbers work, WZ call numbers, and collections and locations.

Classification Systems

Think what it would be like to use a library whose books were arranged in no special order. It would take forever to find what you need. Fortunately, even the smallest libraries use some sort of system to arrange their books. Classification systems organize library collections into subject-related categories, so similar topics will be grouped together on the shelf.

There are three major classification systems, Dewey Decimal, Library of Congress, and Superintendent of Documents. The Dewey Decimal (DDC) system uses 10 main subject categories and is used by medium to small libraries. The Library of Congress (LC) system uses 21 broad subject categories, identified by single letters of the alphabet, A through Z (I, O, W, X, and Y are not used). The UAF Rasmuson Library along with many other academic, research and large libraries use the LC classification system. Materials in the Government Documents collection, however, use the Superintendent of Documents system (SuDocs) which are grouped by issuing agency, rather than subject.

This means that you can walk into any library which uses the Dewey (DC) system and mathematics books will have a call number between 510-519. You can walk into any library that uses the Library of Congress (LC) system and the call number for mathematics books will begin with QA. And you can visit any Government Documents collection that uses the SuDocs system and call number for Environmental Protection Agency documents will begin with EP.

Call Numbers

Library of Congress Call Numbers

Books are shelved in the library by call number. A call number is a unique identification code assigned to each book that clearly identifies it from other books (call numbers are also used for other items in the library such as periodicals). It consists of a combination of numbers and letters. Each call number consists of at least two parts, the classification number and the Cutter number (author or book number). But may contain as many as six parts: location code, classification number, Cutter number, edition date, volume number, and copy number. Call numbers are based on the Library of Congress classification system which is used by UAF libraries. Knowing how call numbers work is essential for locating materials on the shelves.

SuDocs Call Numbers

SuDocs call numbers, used on government publications, are constructed to represent the government agencies that produced them. Thus numbers starting with A are from the Department of Agriculture, with C the Department of Commerce, with NAS from the National Aeronautics and Space Administration, and so on. Therefore publications in the Government Documents collection of the library are not grouped on the shelves by subject because most agencies publish on wide varieties of subjects. Instead they are grouped by agency. One or more numbers immediately following the initial letter or letters represent a subdivision of the primary agency. Thus T22 is for the Internal Revenue Service in the Treasury Department.

SuDocs call numbers have a colon, :, in the middle. That separates the first part of the call number, the stem or agency number, from the second part, the book number. You can always distinguish a SuDocs call number from an LC number by the colon.

Be aware that LC and SuDocs call numbers usually appear in horizontal format on records in catalogs and indexes and in vertical format on the spines of books and other publications. In the latter, the dot is assumed at the start of the third line.

WZ Call Numbers

Occasionally in the catalog you will find call numbers that begin with the letters TEMP WZ or TECH WZ.

These are temporary, non-Library of Congress call numbers for books which are being processed and are not yet on the public shelves. You may request that an item with a WZ call number be rush processed so that you can check it out. To make a RUSH processing request, make a printout from the catalog and see the Reference Librarian for a RUSH request form.

Collections and Locations

There are many different collections located within UAF libraries. The collection designator together with a call number shows you where to find the item you want. Collection designators such as ALASKA, DOCS, PER, JUVL, OVRSZ and REF may appear either before or after the call number. If there is no collection designator noted, the title you want is in the general book collection.

For example:

  • ALASKA PER Q127 A48 A58 v.12 no.1
  • Y3 W58/3-3:1/971 DOCS
This page was last modified on April 23, 2015