Library Classification Systems in the U.S.: Basic Ideas and Examples

This article offers a basic introduction to classification in the context of librarianship in the United States with an aim toward filling gaps in formal education and practical experience. The article defines the concept of classification and discusses the goals and purposes of classification, both functional and intellectual. Overviews of two common classification systems frequently used in U.S. libraries are presented: Dewey Decimal Classification (DDC), Library of Congress Classification (LCC), as well as an introduction to a group of classifications known as “reader-interest classifications.”