Step 2. Access Gather information and sources
Library Catalog | Article Databases | Journal Locator (PDF) | Subject Guides | LC Call #
Parts of a call number
Finding an item on shelf
Library of Congress Classification System
Items are arranged on the shelves from left to right, top to bottom within each section of shelving, according to call numbers. Call numbers are arranged in alphabetical order by class letters, and then numerically, as outlined below:
In general, call numbers are arranged first in alphabetical sequence...
| AS | AY | B | BF | DC | G | GT | PE | RA | T | TX |
...then in numerical sequence. Read the second line, or the first set of numbers, as a WHOLE number.
| AS 23.6 |
AS 23.7 |
AS 123 |
AY 8 |
AY 12 |
AY 79 |
...then by a combination of alphabetical and decimal order on the third line.
Subsequent lines with both letters and numbers are read alphabetically and
then in decimal order; subsequent lines with only numbers are read as whole
numbers. For example, correct call number order is shown below for a sampling
of items:
| LB 1075 C29 A342 2000 |
LB 1725 U55 A35 |
LB 1725 U6 B3 |
LB 1725 U63 1999 |
LB 1725.1 A5 2005 |
LB 1725.3 D5 |
More Examples
| Q | Q | Q | Letters are in alphabetical order. |
| 76.555 | 76.6 | 76.65 | Number(s) BEFORE the decimal point are in numeric order. Number(s) AFTER the decimal point are in decimal order. |
| B105 | B3 | B33 | Letters are in alphabetical order.
Numbers are in decimal order. |
| P267 | P28 | R4 | Letters are in alphabetical order.
Numbers are in decimal order. |
| 1999 | 1997 | 2001 | Publication dates. |
| Q | QA | QB | Letters are in alphabetical order. |
| 5 | 72.46 | 920.3 | Number(s) BEFORE the decimal point are in numeric order. Number(s) AFTER the decimal point are in decimal order. |
| B28 | E42 | M2 | Letters are in alphabetical order. Numbers are in decimal order. |
| O299 | PO2 | P4 | Letters are in alphabetical order. Numbers are in decimal order. |
| 2001 | 2004 | 1999 | Publication dates. |
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