Although collections of books may be arranged in various ways, most libraries arrange books according to subject so that related materials are found in the same general area on the shelf. The subject classification systems most commonly used in American libraries are Library of Congress (LC) Classification and Dewey Decimal Classification. Academic libraries such as the College of Marin Library generally use LC classification while public libraries use Dewey. Following is an abbreviated outline of the Library of Congress Classification System.

A        GENERAL WORKS
AE             Encyclopedias
AY             Almanacs

B        PHILOSOPHY AND RELIGION
B-BJ          Philosophy
BF             Psychology
BL-BX        Religion

C        HISTORY--AUXILIARY SCIENCES
CC            Archaeology
CT            General Biography

D        HISTORY: GENERAL AND OLD WORLD
DA-DR     Europe
DS           Asia
DT           Africa
DU          Australia and Oceania

E-F     HISTORY: AMERICA

G        GEOGRAPHY AND ANTHROPOLOGY
GB            Physical Geography
GC            Oceanography
GN            Anthropology
GR            Folklore
GV            Sports, Recreation, Leisure

H        SOCIAL SCIENCE
HA           Statistics
HB-HD      Economics
HF            Business and Accounting
HM           Sociology
HV            Law Enforcement

J        POLITICAL SCIENCE
JK             United States
JN             Europe
JQ             Asia, Africa
JX              International Relations

K        LAW

L        EDUCATION

M        MUSIC

N        FINE ARTS
NA            Architecture
NB            Sculpture
NC            Graphic Arts
ND            Painting
NE            Engraving
NK            Ceramics, Textiles

P        LANGUAGE AND LITERATURE
PA              Classical Languages and Literature
PC              Romance Languages
PE              English Language
PF              German Languages
PL               Asian and African Languages and Literature
PN              Theater, Speech, Journalism
PQ              Romance Literature
PR              English Literature
PS              American Literature
PT              German Literature

Q        SCIENCE
QA              Mathematics
QB              Astronomy
QC              Physics
QD              Chemistry
QE              Geology
QH              Natural History and General Biology
QK              Botany
QL               Zoology
QM              Human Anatomy
QP              Physiology
QR              Bacteriology

R        MEDICINE
RK              Dentistry
RT              Nursing

S        AGRICULTURE

T        TECHNOLOGY
TA              General and Civil Engineering
TH              Building Construction
TJ               Mechanical Engineering and Machinery
TK              Electrical Engineering
TL              Motor Vehicles
TN              Mineral Industries
TP              Chemical Technology
TR              Photography
TS              Manufactures
TT              Trades
TX              Home Economics

U        MILITARY SCIENCE

V        NAVAL SCIENCE

Z        BIBLIOGRAPHY AND LIBRARY SCIENCE