Here's an outline of the major subject areas in the LC system:
A - General Works - encyclopedias
B - Philosophy, Psychology, Religion
C - History - Auxiliary Sciences
D - History (except American)
E - General U.S. History
F - Local U.S. History
G - Geography, Anthropology, Recreation
H - Social Sciences
J - Political Science
K - Law
L - Education
M - Music
N - Fine Arts
P - Language and Literature
Q - Science
R - Medicine
S - Agriculture
T- Technology
U - Military
V - Naval Science
Z - Bibliography and Library Science
Read call numbers line by line
A - BL: 2nd Floor
BM - HC: 3rd Floor
HD - K: 3rd Floor
L - N: 1st Floor
P - Z: 1st Floor