The Superintendent of Documents Classification System (SuDocs) was developed by Adelaide Rosalie Hasse for the Government Printing Office (GPO) around the turn of the century. Unlike classification systems such as the Dewey Decimal System (DDC) or the Library of Congress Classification System (LC), SuDocs was developed for a narrow and specific purpose: to classify publications of the U.S. government produced and distributed by the GPO.

Where you are most likely to encounter the SuDocs system is in the government documents section of a Federal Depository Library. A Depository Library is an institution which receives a selection of all material produced by the GPO at regular intervals. While the documents could be integrated into the main collection and organized by DDC or LC, government publications come in a wide variety of formats: pamphlets, microfilm, maps, etc. instead of mostly books as in a typical library collection. Also, patrons approach government information with different needs and search strategies than they approach the general collection.

Unlike DDC and LC, where materials are organized by subject, in SuDocs, government publications are organized by the government agency which responsible for producing them. This has two drawbacks. Information on a particular topic is sometimes scattered in different places in the collection. Also, when an agency is transferred from one department of the government to another, the SuDoc number changes as a result. Documents from several agencies that have changed hands many times are found in different places. However, the efficiency and convenience of the SuDocs organizational structure outweigh these minor drawbacks.

A SuDocs call number consists of three elements: the author symbol, the series designation, and the book number. The author symbol and the series designation together are called the class stem.

The author symbol

The author symbol does not designate "author" in the traditional sense, i.e. the person who actually wrote the publication. Here, the "author" is the department and agency of the US government which produced the publication. The symbol begins with one or two letters designating the department (see list of classes above), usually the first letter(s) in the name of that department. For example, A is the Department of Agriculture, C is the Department of Commerce, HE is the Department of Health and Human Services, JU is the judiciary and PR is the presidency. X and Y are reserved for Congress, and Z is unused. The designation for the new cabinet-level Office of Homeland Security has not been decided yet, but it will probably be something like H or HS, though I am hoping for HO or even KGB myself.

A number follows which indicates the organization within that agency. A 1 indicates the parent organization. In some classes, numbers were assigned alphabetically, with newly created agencies tacked onto the end. For example, A1 is the Department of Agriculture, A13 is the Forest Service, and A68 is the Rural Electrification Administration. In others, such as the Department of Defense (D) and the Department of Health and Human Services (HE), the classes have been reorganized in a hierarchical manner to reflect the structure of that department instead of an arbitrary numerical designation.

An exception to this is PR, the presidency. The number following PR designates which president. PR42 would be Bill Clinton, the 42nd president.

The series designation

The series designation denotes the type of publication. They following are reserved series designations, though SuDocs is not limited to these alone:

.1: Annual reports
.2: General publications
.3: Bulletins
.4: Circulars
.5: Laws
.6: Regulations, rules, and instructions
.7: Press releases
.8: Handbooks, manuals, guides
.9: Bibliographies and lists of publications
.10: Directories
.11: Maps and charts
.12: Posters
.13: Forms
.14: Addresses, lectures, etc.

A slash (/) may be used to further specify the type of publication. An example of this is the following:

4: Circulars
4/A: Separates from Circulars (numbered)
4/B: Separates from Circulars (unnumbered)
4/2: Administrative Circulars
4/3: Technical Circulars

The book number

Following the colon at the end of the class stem is the book number. This "number" is a unique combination of letters and numbers which differentiates it from other publications. In the case of numbered publications such as serials or annual publications such as yearbooks, the number is simply the volume and issue number or the year. In the case of unique publications, the book number is a Cutter number generated from the title (and not the author or agency) of the publication. Cutter numbers are combinations of letters and numbers which are unique identifiers assigned to materials to differentiate them from other items with the same call number. Cutter numbers are not unique to SuDocs; they are used in LC and DDC.

Joe Morehead, Introduction to United States Government Information Sources.
An Explanation of the Superintendent of Documents Classification System (
GPO Classification Manual (