Library of Congress Call Numbers

The MIT Libraries use the Library of Congress Classification system when assigning call numbers to books. A call number is like an address. It determines the book location (or other item) on the shelf

When using Barton, the MIT Libraries online catalog, a call number usually accompanies the record of an item. In the catalog, the call number appears on one line, like this:

LIBRARY	COLLECTION	CALL NUMBER	Vol/Issue	STATUS/DUE DATE	Notes
Dewey Library	Stacks	HD1234.23 .P98 1992		In Library		More info

On the actual item, the number will usually appear on a label like this:

HD1234.23
.P98
1992

Barton Screen Display Explanation

LIBRARY
This represents the MIT library in which the title can be found. In this instance, the Dewey Library.
*Please note that there are 9 libraries in the MIT Libraries System, in addition to the Libraries Storage Annex. Be sure to make a note of the library for the title found before you visit the library to look for the item.

COLLECTION
This represents the location within the library where the item is located. In this example, the item is in the Dewey stacks. If you are unsure of the location, please ask library staff for assistance.

CALL NUMBER
This provides the specific location of the item on the shelf. The call number is usually found on a label at the bottom of a book's spine.

The parts of a call number:

HD --The first part of the call number is alphabetic. To find it, locate the H section, and then the part within it labelled HD. For example, HD would come before HG and after HB.

1234.23 --The second part is numeric and should be read as a whole number. The numbers may or may not have decimal points; but when they do, treat them as such. For example, HD1234 comes before HD1234.23 and HD1233 comes before HD1234.

.P98 --This part has to be read in two ways; first alphabetically, then numerically. This time the number should be read as a decimal!

HD1234.23.P would be located between HD1234.23.L and HD1234.23.T, for example.
HD1234.23 .P98 would be somewhere between HD1234.23.P961 and HD1234.23.P998.

Some call numbers have yet a third alpha-numeric line. Read the number as a decimal.

1992--This number indicates the year; generally the year of publication for that particular volume.

STATUS

This indicates not only if a title is "In Library", but anything special about the book. Other statuses may include: "In Bindery," "On Order," or "Local Process." For an explanation of any status, please consult library staff.

This page was last updated on 09/19/07

Library of Congress Call Numbers

LIBRARY

COLLECTION

CALL NUMBER

Vol/Issue

STATUS/DUE DATE

Notes