What is a call number? Every book in the library is given a unique call number to serve as an address for locating the book on the shelf. The call number itself is composed of two parts -- Dewey Decimal Classification and the Cutter number. The Dewey Decimal Classification System was developed in the late nineteenth century by Mevil Dewey as a system of organizing materials in a library by topic. The Dewey system has TEN main classes:
| 900 Geography, history, etc. | 950 Asian History |
| 910 Geography and travel | 960 African History |
| 920 Biography | 970 North American History |
| 930 Ancient history | 980 South American History |
| 940 European history | 990 Other Nations |
Each of these divisions is divided again into TEN subdivisions,
each more specific. For example, 970 North American History, is divided
like this:
| 970 North American history | 975 SE United States |
| 971 Canada | 976 South Central United States |
| 972 Middle America | 977 North Central United States |
| 973 United States | 978 Western United States |
| 974 NE United States | 979 Great Basin, Pacific Slope |
Each one of the ten subdivisions are further subdivided and arranged
decimally, making the number even more specific. For example, United States
history is 973. It is further subdivided like this:
| 973.1 U.S. history to 1607 | 973.6 U.S. history 1845-1861 |
| 973.2 U.S. history 1607-1775 | 973.7 U.S. history 1861-1865 |
| 973.3 U.S. history 1775-1789 | 973.8 U.S. history 1865-1901 |
| 973.4 U.S. history 1789-1809 | 973.9 U.S. history 1901- |
| 973.5 U.S. history 1809-1845 |
Books are shelved in decimal order, not by whole number. For example:
331
331.1
331.198
331.2