The Dewey Decimal Classification (DDC) is a system used to organize library materials by assigning a unique number to each subject. Developed by Melvil Dewey in 1876, it helps librarians categorize books and other resources, making it easier for users to find information. The system divides knowledge into ten main classes, each represented by a three-digit number. Each main class is further divided into subclasses and specific topics, allowing for detailed organization. For example, the class for literature is represented by the number 800, while specific genres or authors receive additional digits for precise classification. This hierarchical structure enhances accessibility in libraries.