| Class A | General Works |
| Class B | Philosophy. Psychology. Religion |
| Class C-F | History |
| Class G | Geography. Anthropology. Recreation |
| Class H | Social Sciences |
| Class J | Political Science |
| Class K | Law |
| Class L | Education |
| Class M | Music |
| Class N | Fine Arts |
| Class P | Language and Literature |
| Class Q | Science (General) |
| Class QA | Mathematics. Computer Science (Software) |
| Class QB-QE | Astronomy. Physics. Chemistry. Geology |
| Class QH-QL | Natural History. Biology. Ecology. Botany. Zoology |
| Class QM-QR | Human Anatomy. Physiology. Microbiology |
| Class R | Medicine |
| Class S | Agriculture |
| Class T | Technology |
| Class U-Z | Military Science. Naval Science. Bibliography. Library Science |
