Dewey Decimal Classification System
Libraries are simply large collections of information sources. The information that libraries contain is usually in the form of books but you will also find newspapers, magazines, journals, video tapes, audio tapes, CD-ROM discs, DVD discs, maps and maybe even collections of leaflets. Of course a collection of information is useless unless it is organised is some way and that is where the Dewey Decimal Classification system comes in. The DDC or Dewey (as it is often known) is the system used by most public and academic libraries in the U.K. to organise their collections of books and other resources.
You do not need to know a great deal about the DDC just the fact that it lists many different subjects and gives each of them a number which is then stuck on the spine of the book. These numbers are known as subject numbers, class or classification numbers, or class marks. The books are then arranged on the library shelves in numerical order.
The Ten Main Subject Groups
The DDC contains many thousands of numbers arranged into ten major subject groups; if you know only the numbers of these ten groups you will have a good chance of finding your way round the library, eliminating 90 per cent of the stock and locating just that 10 per cent that interests you.
The ten main subjects and numbers of the DDC are:
| 000 | Generalities | 100 | Philosophy and Psychology |
| 200 | Religion | 300 | Social Sciences |
| 400 | Language | 500 | Natural Sciences & Mathematics |
| 600 | Technology (Applied Sciences) | 700 | The Arts |
| 800 | Literature & Rhetoric | 900 | Geography & History |
The One Hundred Main Subjects
Each of these ten subjects are subdivided into ten more subjects or classes giving 100 major subdivisions (as they are known). If you know the numbers of the two or three major subdivisions that relate to your course or interest you have an extremely powerful tool for finding your way round even the largest of libraries.
These 100 major subdivisions are given in this table; browse through it and find the subjects that you are studying or that you are interested in and note down their subject numbers.
| 000 Generalities/I.T. | 100 Philosophy and Psychology | ||
| 010 | I.T., Computer Applications, Bibliography | 110 | Metaphysics |
| 020 | Library & information sciences | 120 | Epistemology, causation, humankind |
| 030 | General encyclopedic works | 130 | Paranormal phenomena |
| 040 | Unassigned | 140 | Specific philosophical schools |
| 050 | General serials & their indexes | 150 | Psychology |
| 060 | General organizations & museology | 160 | Logic |
| 070 | News media, journalism, publishing | 170 | Ethics (moral philosophy) |
| 080 | General collections | 180 | Ancient, medieval, Oriental philosophy |
| 090 | Manuscripts & rare books | 190 | Modern Western philosophy |
| 200 Religion | 300 Social Sciences | ||
| 210 | Natural theology | 300 | Sociology and anthropology |
| 220 | Bible | 310 | General statistics |
| 230 | Christian theology | 320 | Political science |
| 240 | Christian moral & devotional theology | 330 | Economics |
| 250 | Christian orders & local church | 340 | Law |
| 260 | Christian social theology | 350 | Public administration |
| 270 | Christian social theology | 360 | Social services; associations |
| 280 | Christian denominations & sects | 370 | Education |
| 290 | Other & comparative religions | 380 | Commerce, communications, transport |
| 390 | Customs, etiquette, folklore | ||
| 400 Language | 500 Natural Sciences & Mathematics | ||
| 410 | Linguistics | 510 | Mathematics |
| 420 | English & Old English | 520 | Astronomy & allied sciences |
| 430 | Germanic languages German | 530 | Physics |
| 440 | Romance languages French | 540 | Chemistry & allied sciences |
| 450 | Italian, Romanian languages | 550 | Earth sciences |
| 460 | Spanish & Portuguese languages | 560 | Paleontology, paleozoology |
| 470 | ltalic languages, Latin | 570 | Life sciences |
| 480 | Hellenic languages, Classical Greek | 580 | Botanical sciences |
| 490 | Other languages | 590 | Zoological sciences |
| 600 Technology (Applied Sciences) | 700 The Arts | ||
| 600 | General technology | 710 | Civic & landscape art |
| 610 | Medical sciences and medicine | 720 | Architecture |
| 620 | Engineering & allied operations | 730 | Plastic arts, sculpture |
| 630 | Agriculture | 740 | Drawing & decorative arts |
| 640 | Home economics & family living | 750 | Painting & paintings (museums) |
| 650 | Management & auxiliary services | 760 | Graphic arts, printmaking & prints, postage stamps |
| 660 | Chemical engineering | 770 | Photography & photographs |
| 670 | Manufacturing | 780 | Music |
| 680 | Manufacture for specific uses | 790 | Recreational & performing arts |
| 690 | Buildings | ||
| 800 Literature & Rhetoric | 900 Geography & History | ||
| 810 | American literature | 900 | World History |
| 820 | English & Old English literatures | 910 | Geography and travel |
| 830 | Literatures of Germanic languages | 920 | Biography, genealogy, insignia |
| 840 | Literatures of Romance languages | 930 | History of the ancient world |
| 850 | Italian, Romanian literatures | 940 | General history of Europe |
| 860 | Spanish & Portuguese literatures | 950 | General history of Asia, Far East |
| 870 | Italic literatures, Latin | 960 | General history of Africa |
| 880 | Hellenic literatures, Classical Greek | 970 | General history of North America |
| 890 | Literatures of other languages | 980 | General history of South America |
| 990 | General history of other areas | ||