Here's why:
* Organization: Libraries use call numbers to organize their collections in a logical and consistent manner. This helps patrons find books quickly and efficiently.
* Classification Systems: Call numbers are based on classification systems like the Dewey Decimal System or the Library of Congress Classification System. These systems categorize books by subject, making it easier to find related materials.
Note: While nonfiction books almost always have call numbers, some libraries might have exceptions, such as:
* Very small collections: Smaller libraries may not have a formal call number system.
* Special collections: Some collections, like government documents or rare books, might have their own unique numbering systems.
If you're unsure if a specific nonfiction book has a call number, you can always ask a librarian for assistance.