# Identify books in library

![The number by which a book is identified](https://3526924997-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-MIgCXXRd_zYwMrU-RaQ%2F-MSpOl9e6U-eMAui2AUB%2F-MSpSnvzBbbLef9on6hV%2Fimage.png?alt=media\&token=36d98091-e458-4260-ab1a-013badad8d08)

Dewey decimal system - books in a library are arranged by subject. These codes can be committed to memory.

### Codes

Reference: <https://archive.org/details/decimal18v2dewe>

| #   | Subject                                        |
| --- | ---------------------------------------------- |
| 000 | Computer science, information and general work |
| 100 | Philosophy and psychology                      |
| 200 | Religion                                       |
| 300 | Social Sciences                                |
| 400 | Language                                       |
| 500 | Science                                        |
| 600 | Technology                                     |
| 700 | Art and recreation                             |
| 800 | Literature                                     |
| 900 | History and geography                          |