Dewey decimal code 800 stands for literature books and 900 stands for geography, history, culture and social books. Dewey decimal coding is a kind of book classification, which is used to organize and manage the library's book resources. In Dewey decimal coding, 800 and 900 are two different classification numbers, representing different subject categories respectively. 800 represents books on literature, rhetoric, language and style in works. 900 stands for books on geography, history, culture and society.