How does the Dewey Decimal system work?

The Christchurch City Libraries uses the Dewey Decimal System to classify non-fiction material. Subjects are divided into ten main groups which are represented by series of numbers.

000
General works (including encyclopedias and general reference)
100
Philosophy and psychology
200
Religion
300
Social sciences
400
Languages
500
Sciences
600
Applied sciences / Technology
700
The Arts
800
Literature
900
Geography, history and travel

Each of these ten groups is divided into more specialised subject fields, again represented numerically, for example:

500
Sciences
540
Chemistry
546
Inorganic chemistry
700
The Arts
750
Paintings and painting
751.422
Watercolour technique

Certain features are common to each of the groups, e.g. the first numbers in any area are always general works on that subject and longer numbers represent more detailed aspects.

All non-fiction material is usually shelved in numerical order, according to its assigned Dewey number.

Fiction is shelved alphabetically by author, except fiction in foreign languages which is classified at 830 - 899.

Other points to note are

  • There is always a decimal point after the first three numbers
  • The three letters which follow the number are usually the first three letters of the author's surname and help to distinguish that particular book from others at the same number
  • Not For Loan "NOT FOR LOAN" on the spine indicates a reference book, which may only be used in the library
  • "B" on the spine indicates a biography
  • "NZ" indicates a New Zealand book
  • Piko piko The Green Piko Piko symbol indicates Ngā Pounamu Māori collection & Māori collections at Community Libraries
  • Koru White Koru on black label is used on items with Māori content not held in a special Māori collection
Architecture 720 - 729 Literature 800 - 899
Arts & Crafts 700 - 769 Management 650 - 659
Building 690 - 699 Manufacturing 670 - 689
Biography 920 - 929 Medicine 610 - 619
Business 650 - 659 Music 780 - 789
Chemical Engineering 660 - 669 Needlecrafts 746.4
Computers 004 - 006 Painting 750 - 759
Cooking 640 - 641 Performing Arts 790 - 792
Customs 390 - 399 Pets 636 - 639
Economics 330 - 339 Philosophy 100 - 199
Education 370 - 379 Political Science 320 - 329
Encyclopedias, collected facts 030 - 039 Psychology 130 - 159
Engineering 620 - 629 Public Services 350 - 359
Folklore 398 Pure Sciences 500 - 599
Gardening 635 - 635.9 Religions 200 - 299
Geography 910 - 999 Sciences 500 - 599
Graphic Arts 760 - 769 Sculpture 730 - 739
Health 610 - 619 Social Services 360 - 369
History 900 - 999 Sociology 300 - 309
Home Economics 640 - 649 Sports 796
Journalism 070 - 079 Technology 600 - 699
Landscape Art 710 - 719 Transport 380 - 389; 623 - 629
Languages 400 - 499 Travel 910 - 999
Law 340 - 349

The Dewey Decimal Classification is (c) 1996-2001 OCLC Online Computer Library Center, Incorporated. DDC, Dewey, and Dewey Decimal Classification are registered trademarks of OCLC Online Computer Library Center, Incorporated.