AE	Encyclopedias
AL	Indexes
AY	Almanacs
BF	Psychology
BJ	Ethics
BM	Judaism
BP	Islam
BR	Christianity
CB	Civilization & Culture
CS	Genealogy
CT	Biography (General)
D	History (General)
DA	Great Britain
DE	Classical Antiquity
DS	History of Asia
DT - DX	History of Africa, Australia, New Zealand, etc
E - F	History: America (Western Hemisphere)
GB	Physical Geography
GN	Anthropology
GT	Manners and Customs
GV	Recreation (Sports, Dance)
HA	Statistics
HB- HD	Economics
HE	Transportation
HG - HJ	Finance
HM	Sociology
HQ	Family, Marriage, Sexual Life
HV	Social/Public Welfare, Alcoholism, Drug Abuse, Criminology, Penology
J	Political Science
K	Law (General)
LA	History of Education
LB	Theory and Practice
ML	Literature of Music
MT	Music Instruction and Study
NA	Architecture
ND	Painting
PE	English Language
PN	Criticisms, Poetry, Prose, Journalism
QA	Mathematics
QC	Physics
QD	Chemistry
QH	General Biology
QM	Human Anatomy
QP	Physiology
RG	Gynecology and Obstetrics
RS	Pharmacy
RT	Nursing
S	Agriculture
T	Technology
U	Military Science
V	Naval Science
Z	Bibliography, Library Science