| 000 | General topic books like encyclopedias |
| 100 | Philiosophy and psychology, an example would be a book about ghosts |
| 200 | Religion |
| 300 | Social Sciences, books about politics and laws |
| 400 | Language, books about linguistics and foregin languages |
| 500 | Natural Sciences and Math, examples would be books on astronomy and animals |
| 600 | Technology and Applied Sciences, examples would be books on computers and medicine |
| 700 | Art, examples would be drawing and painting |
| 800 | Literature, examples would be fairy tales |
| 900 | Geography and History, examples would be books on american history |