Besides the types of materials the different libraries contain, public and high school libraries also differ from college and university libraries in the systems they use to classify their resources.
Public and school libraries usually use the Dewey Decimal classification system, while college and university libraries usually use the Library of Congress Classification System.
Differences Between Dewey and LC
| Dewey Call Number | Library of Congress Call Number |
| 571 .0919 ROA |
QH 327 .R63 2010 |
The most obvious difference is the presence of letters in the LC call number; these represent subject divisions. Where the Dewey Classification system has 10 topics areas represented by 000-900, the LC system is most often used by academic libraries because it allows libraries to be more specific in their subject classifications as LC has 21 divisions represented by A-Z, omitting I, O, W (used by medical libraries), V, and Y.
See So How Do I Find a Book? for tips on reading LC Call Numbers.
To see the detailed LC classification outline including subject subdivsions...
A - AZ General Works
B - BX Philosophy, Psychology, Religion
C - CT Auxiliary Sciences of History
D-DX World History and History of Europe, Asia, Africa, New Zealand
E-F History of the Americas
G- GV Geography, Anthropology, Recreation
H-HX Social Sciences
J-JZ Political Science
K-KZ Law
L-LT Education
M-MT Music and Books on Music
N-NX Fine Arts
P-PZ Language and Literature
Q-QR Science
R-RZ Medicine
S-SK Agriculture (including Hunting)
T-TX Technology (does not include most Computer Science which is in the Qs)
U-UH Military Science
V-VM Naval Science
Z-ZA Bibliography, Library Science, Information Resources (General)