Dewey Decimal System
| Field | Books |
| Went Obsolete | Never |
| Made Obsolete By | Not obsolete |
| Knowledge Assumed | Ability to Read, Understand Basic Math |
| When useful | Library |
Educational books are organized into ten classes, which were then subdivided further. To find a book, you would look up the the book by name or topic in a catalog to find the Dewey Decimal number, then locate the book on the shelve using the Dewey Decimal System.
The system is also useful for just looking up a book without using the catalog. For instance, when looking for a book on magnetism, one would look up the “5xx” category, for Science, then “x3x” for Physics, ending at “538” for magnetism
While it's true that the system is flawed, being based on a 19th-century system of knowledge which, for instance, alloted 90% of the Religion numbers to Christianity and still including a separate category for phrenology (139), it is still very much in use and undoubtedly will be for some time. DDC is not only used to shelve books, but to bring like resources together virtually. Classification systems of all kinds continue to thrive and find new uses beyond just shelving books.
