| 000 | General Works | encyclopedias, computers, almanacs, news media |
| 100 | Philosophy & Psychology | what people think or feel |
| 200 | Religion & Mythology | religion, mythology, what people believe |
| 300 | Social Sciences | governemt, military, social problems, folklore |
| 400 | Languages | dictionaries, grammar, books written in or about other languages |
| 500 | Natural Science & Math | math, astronomy, nature, physics, earth |
| 600 | Technology | medicine, engineering, agriculture, pets, manufacturing |
| 700 | Arts & Recreation | art, music, photography, sports |
| 800 | Literature & Speaking | stories, poems, speeches |
| 900 | Geography & History | maps, travel, history, genealogy, flags |