Dewey Decimal Classification System
| This article originally appeared in Printed Sources: A Guide to Published Genealogical Records, edited by Kory L. Meyerink. |
Introduction
Most public libraries use the Dewey Decimal Classification System, which was developed in 1873 by Melvin Dewey for the Amherst College Library in Amherst, Massachusetts. This system classifies books within ten basic groups or classes of knowledge, as shown below.
Dewey Decimal Classification System
| 000 | Generalities |
| 001.9 | Controversial and spurious knowledge |
| 011 | General bibliographies |
| 030 | Encyclopedias |
| 070 | Journalism |
| 100 | Philosophy |
| 150 | Psychology |
| 170 | Ethics |
| 180 | Philosophy |
| 190 | Modern Western philosophy |
| 200 | Religion |
| 220 | Bible |
| 231-239 | Christianity |
| 300 | Social sciences |
| 320 | Political science |
| 330 | Economics |
| 340 | |
| 360 | Social services |
| 370 | Education |
| 380 | Commerce and communication |
| 390 | Customs and folklore |
| 398.2 | Folklore and fairy tales |
| 400 | Language |
| 420 | English |
| 430 | German |
| 440 | French |
| 450 | Italian |
| 460 | Spanish, Portuguese |
| 470 | Latin |
| 480 | Greek |
| 500 | Pure sciences |
| 510 | Mathematics |
| 520 | Astronomy |
| 530 | Physics |
| 540 | Chemistry |
| 550 | Earth sciences |
| 570 | Life sciences |
| 580 | Botany |
| 590 | Zoology |
| 600 | Technology |
| 610 | Medicine |
| 620 | Engineering |
| 630 | Agriculture |
| 640 | Home economics |
| 650 | Managerial services |
| 670 | Manufacturing |
| 690 | Buildings |
| 700 | The arts |
| 712 | Landscape design |
| 720 | Architecture |
| 730 | Sculpture |
| 745.1 | Antiques |
| 750 | Painting |
| 760 | Graphic arts |
| 770 | Photography |
| 780 | Music |
| 790 | Recreation and performing arts |
| 800 | Literature |
| 900 | Geography and history |
| 920 | Biography |
| 929 | Genealogy |
| 930 | Ancient world history |
| 940 | European history |
| 950 | Asiatic history |
| 970 | North American history |
| 980 | South American history |
Dewey Decimal System Numbers for Regions and States within the United States
| United States | 973 |
| Within the Dewey system, states are grouped by region: | |
| Northeastern states | 974 |
| Southeastern states | 975 |
| South central states | 976 |
| North central states | 977 |
| Western states | 978 |
| Pacific states | 979 |
| States: | |
| Alabama | 976.1 |
| Alaska | 979.8 |
| Arizona | 979.1 |
| Arkansas | 976.7 |
| California | 979.4 |
| Colorado | 978.8 |
| Connecticut | 974.6 |
| Delaware | 975.1 |
| District of Columbia | 975.3 |
| Florida | 975.9 |
| Georgia | 975.8 |
| Hawaii | 996.9 |
| Idaho | 979.6 |
| Illinois | 977.3 |
| Indiana | 977.2 |
| Iowa | 977.7 |
| Kansas | 978.1 |
| Kentucky | 976.9 |
| Louisiana | 976.3 |
| Maine | 974.1 |
| Maryland | 975.2 |
| Massachusetts | 974.4 |
| Michigan | 977.4 |
| Minnesota | 977.6 |
| Mississippi | 976.2 |
| Missouri | 977.8 |
| Montana | 978.6 |
| Nebraska | 978.2 |
| Nevada | 979.3 |
| New Hampshire | 974.2 |
| New Jersey | 974.9 |
| New Mexico | 978.9 |
| New York | 974.7 |
| North Carolina | 975.6 |
| North Dakota | 978.4 |
| Ohio | 977.1 |
| Oklahoma | 976.6 |
| Oregon | 979.5 |
| Pennsylvania | 974.8 |
| Rhode Island | 974.5 |
| South Carolina | 975.7 |
| South Dakota | 975.7 |
| Tennessee | 976.8 |
| Texas | 976.4 |
| Utah | 979.2 |
| Vermont | 974.3 |
| Virginia | 975.5 |
| Washington | 979.7 |
| West Virginia | 975.4 |
| Wisconsin | 977.5 |
| Wyoming | 978.7 |
