Most people have some classification systems in their home. In a kitchen, for example, many of us keep all the silverware together, all the canned food together, and all the pots together.
Supermarkets provide another example of a classification system.
Meats are together, dairy products are together, and fresh produce is in one place. Imagine trying to find what one needed if items were scattered randomly on the shelves, or if they were arranged alphabetically, placing a pples next to beans next to cheese next to dog food. In libraries, as elsewhere, having a classification system helps people find things. Books about a particular field of knowledge shelved together or near each other, whether that field is music, education or geology. This system helps the researcher find books by browsing, and also assigns specific locations for books on the shelf for easy access.