| A | | General Works |
| | AE | | Encyclopedias |
| | AG | | Dictionaries |
| | AI | | Indexes |
| | AY | | Almanacs |
B | | Philosophy/Psychology/Religion |
| | B-BD | | Philosophy |
| | BF | | Psychology |
| | BL-BX | | Religion |
C | | History: Related Fields |
| | CC | | Archaeology |
| | CT | | Biography |
D | | History: (except America) |
E | | History: America (General) & U.S. (General) |
F | | History: U.S. (Local) & North American (except U.S.), Central America, South America |
G | | Geography/Anthropology/Recreation |
| | G-GF | | Geography |
| | GN | | Anthropology |
| | GR | | Folklore |
| | GV | | Recreation |
H | | Social Sciences |
| | HA | | Statistics |
| | HB-HC | | Economics |
| | HD | | Labor (Professions) |
| | HF | | Commerce, Accounting, Advertising |
| | HG | | Finance |
| | HM | | Sociology |
| | HQ | | Family, Marriage, Women's Studies |
| | HV | | Social Pathology, Welfare & Criminology |
J | | Political Science |
| | JK | | United States |
K | | Law |
| | KF | | United States |
| | KFW | | Wisconsin |
L | | Education |
| | LA | | History of Education |
| | LB | | Theory & Practice of Education |
| | LC | | Special Aspects of Education |
M | | Music |
N | | Fine Arts |
| | NA | | Architecture |
| | ND | | Painting |
| | NK | | Decorative Arts |
P | | Languages and Literature |
| | PE | | English Language |
| | PN | | Literary History & Collections |
| | PR | | English Literature |
| | PS | | American Literature |
Q | | Science |
| | QA | | Mathematics (including Computer Sciences) |
| | QC | | Physics |
| | QD | | Chemistry |
| | QM | | Human Anatomy |
| | QP | | Physiology |
| | QR | | Microbiology |
R | | Medicine |
| | RA | | Public Aspects of Medicine |
| | RB | | Pathology |
| | RC | | Internal Medicine & Practice of Medicine |
| | RD | | Surgery |
| | RG | | Gynecology and Obstetrics |
| | RK | | Dentistry |
| | RM | | Therapeutics/Pharmacology |
| | RT | | Nursing |
S | | Agriculture |
| | SB | | Plant Culture |
| | SF | | Animal Culture |
T | | Technology |
| | TA | | Engineering (General)/Civil Engineering |
| | TH | | Building Construction |
| | TJ | | Mechanical Engineering & Machinery |
| | TK | | Electrical Engineering / Electronics / Nuclear Engineering |
| | TL | | Motor Vehicles/Aeronautics/Astronautics |
| | TS | | Manufactures |
U | | Military Science |
V | | Naval Science |
Z | | Bibliography and Library Science |
| | ZA | | Information Resources (General) |