000 Computer science, information & general works
100 Philosophy & psychology
300 Social sciences
700 Arts & recreation
900 History & geography
A call number, with regard to library books, is located on the spine of the book. It is a “unique address” to the location of the book. The library uses the call number system called Dewey Decimal Classification. It was developed by Melvil Dewey. This classification system uses a division of numbers to designate the various classes of subjects. The system uses three digit numbers followed by a decimal point and additional numerals.