The books in the library are arranged on the shelves using the Dewey Decimal Classification (DDC). It is the most widely used library classification system in the world. The word “Dewey” refers to Melvil Dewey (1851-1931) who devised the classification, and was first published in 1876. The second word “Decimal” refers to the base-ten notation that is used to denote and relate subjects. It uses Arabic numerals treated like decimal fractions. Hence the name of the classification is the Dewey Decimal Classification. It is continuously revised to keep pace with knowledge.
Within each area of the Library, the books are shelved by classification number. The classification number (also called the class number or shelf number) appears on a label on the spine of the book. It is made up of the Dewey number and the first three letters of the author's surname or the first three letters of the title, whichever is the main entry on the catalogue. Books are placed on the shelf in increasing numerical order of the Dewey number. When two books have the same Dewey number they are arranged in alphabetical order of the first three letters from the author's name, or, first three letters from the title of the book. The end of each row of shelves indicates the numbers contained in those shelves.
000 is the most general class, and is used for works not limited to any one specific discipline, e.g., encyclopeia, newspapers, general periodicals. This class is also used for certain specialised disciplines that deal with knowledge and information, e.g., computer science, library and information science, journalism. Each of the other main classes (100–900) comprises a major discipline or group of related disciplines.
300 cover the social sciences. It includes sociology, anthropology, statistics, political science, economics, law, public administration, social problems and services, education, commerce, communications, transportation, and customs.
600 is Technology.
Class 900 is devoted primarily to history and geography. It also includes biography and genealogy.
100 covers philosophy, parapsychology and occultism, and psychology.
400 comprise language, linguistics, and specific languages.
700 covers the arts: art in general, fine and decorative arts, music, and the performing arts. Recreation, including sports and games, is also classed in 700.
200 is devoted to Religion.
500 cover the natural sciences and mathematics.
Class 800 covers literature, and includes rhetoric, prose, poetry, drama, etc.