The Government Documents collection is shelved by SuDocs (Superintendent of Documents) number. The basis of the system is to group together governnent publications by author -- author meaning the department, commission, or agency that issued the publication. It is an alphanumeric system.

How it works:
A sample number is J l.14/7: 983

Each agency, commission, department, congress, etc., is assigned a letter designation usually based on the name of the agency.

A = Department of Agriculture
C = Department of Commerce
X,Y = Congressional publications

The letter designation is generally followed by a set of numbers. These numbers specify the particular agency within the department. the type of publication, and the specific publication number or edition.

For example:
J 1.1417:983 is the SuDocs call number for the 1983 edition of Uniform Crime Reports

J = parent agency -- in this case the Department. of Justice
1.14 = the subagency -- in this case the Federal Bureau of Investigation
7 = type of publication -- in this case the Uniform Crime Reports
983 = specific publication -- in this case the 1983 edition

Another example:
L 2.3: 1757 is the call number for the Bureau of Labor Statistics Bulletin no. 1757

L = parent agency -- Department of Labor
2 = subagency - Bureau of Labor Statistics
3 = type of publication -- in this case a bulletin
1757 = specific publication -- Bulletin no. 1757

There are some government agencies that receive special treatment in the assignment of SuDocs numbers. One of the most common of these is Congress and its working committees. The working committees of Congress such as Appropriations, Judiciary, etc. are assigned a combination letter-number designation.

For example:
Y4.J89/2:AR5/5 designates a publication entitled The right to keep and bear arms.

Y = Congress
J89 = Committee on Judiciary
2 = Senate Judiciary (1 stands foe house)
ARS/5 represents the specific publication: the "AR" is taken from the most significant word of the title, in this case "arms"

In order to find a piece on the shelf, it is important to know that numbers are always treated as whole numbers (not decimals as in Dewey or LC classifications) and that any punctuation (periods, slashes) separates whole numbers from each other. Letters within distinct parts of a call number are shelved alphabetically.

For example:

1.201: is shelved before 2.2:
1.3: is shelved before 1.201:
12.2: is shelved before 12.2/2:
Y4.AP6/2: is shelved before Y4.AR5/2: