The Dewey Decimal Classification (or DDC) is a library classification system that divides the breadth of knowledge into 10 enumerated classes from 0-9. These are further divided into 10 divisions, and each division is divided into 10 sections. The 'decimal' in the name comes from the numbers that follow these 3 digits, allowing almost anything to be classified to high degrees of specificity.
The DDC is most commonly used in public and school libraries. Here at Crescent, we use the DDC for non-fiction works. The Toronto Public Library does the same. Understanding the DDC will help you search and find materials at both libraries.
000 Computer science, knowledge, and systems
010 Bibliographies
020 Library and information sciences
030 Encyclopedias and books of facts
040 [Unassigned]
050 Magazines, journals, and serials
060 Associations, organizations, and museums
070 News media, journalism, and publishing
080 Quotations
090 Manuscripts and rare books
100 Philosophy
110 Metaphysics
120 Epistemology
130 Parapsychology and occultism
140 Philosophical schools of thought
150 Psychology
160 Philosophical logic
170 Ethics
180 Ancient, medieval, and Eastern philosophy
190 Modern Western philosophy (19th-century, 20th-century)
200 Religion
210 Philosophy and theory of religion
220 The Bible
230 Christianity
240 Christian practice and observance
250 Christian orders and local church
260 Social and ecclesiastical theology
270 History of Christianity
280 Christian denominations
290 Other religions
300 Social sciences, sociology, and anthropology
310 Statistics
320 Political science
330 Economics
340 Law
350 Public administration and military science
360 Social problems and social services
370 Education
380 Commerce, communications, and transportation
390 Customs, etiquette, and folklore
400 Language
410 Linguistics
420 English and Old English languages
430 German and related languages
440 French and related languages
450 Italian, Romanian, and related languages
460 Spanish, Portuguese, Galician
470 Latin and Italic languages
480 Classical and modern Greek languages
490 Other languages
500 Science
510 Mathematics
520 Astronomy
530 Physics
540 Chemistry
550 Earth sciences and geology
560 Fossils and prehistoric life
570 Biology
580 Plants
590 Animals (Zoology)
600 Technology
610 Medicine and health
620 Engineering
630 Agriculture
640 Home and family management
650 Management and public relations
660 Chemical engineering
670 Manufacturing
680 Manufacture for specific uses
690 Construction of buildings
700 Arts
710 Area planning and landscape architecture
720 Architecture
730 Sculpture, ceramics and metalwork
740 Graphic arts and decorative arts
750 Painting
760 Printmaking and prints
770 Photography, computer art, film, video
780 Music
790 Sports, games and entertainment
800 Literature, rhetoric, and criticism
810 American literature in English
820 English and Old English literatures
830 German and related literatures
840 French and related literatures
850 Italian, Romanian and related literatures
860 Spanish, Portuguese, Galician literatures
870 Latin and Italic literatures
880 Classical and modern Greek literatures
890 Other literatures
900 History
910 Geography and travel
920 Biography and genealogy
930 History of ancient world (to c. 499)
940 History of Europe
950 History of Asia
960 History of Africa
970 History of North America
980 History of South America
990 History of other areas
The DDC uses a system of 3 numbers, sometimes followed by a decimal, to organise material. Each succeeding number becomes more specific. This top-down approach allows you to broaden or narrow your search as necessary.
The first number is the class number. This tells you the breadth of the subject.
ex. 500 Science
The second number is the division number. This tells you what subject area the material is under the class.
510 Mathematics (division)
The third number is the section number. This specifies what part of the subject area the material is about.
511 General principles of mathematics (section)
The decimal is the subject number, which can be anywhere from 1 to 10 digits in length. This tells you, in varying specificity, the exact nature of the material's subject.
511.1 Discrete mathematics (subject)
A call number refers to the label on the bottom of the book spine that gives information about where that book can be found on library shelves. Call numbers are used for all kinds of books, but different collections and types of libraries use different call numbers. Here at Crescent, we use two: one for fiction and one for non-fiction.
Our fiction collection call numbers are simple: a qualifier followed by the first three letters of the author's last name. For non-fiction, we use a combination of the DDC number and the first three letters of the author's last name, sometimes preceded by a qualifier.
No qualifier - typical for MSUS.
J (Juvenile) for Lower School.
YA (Young Adult) for Middle School.
GRA (Graphic Novel) - can be used across schools, here for MSUS. Also includes the volume number (vol.1) to indicate that it is part of a series.
When taking out materials from other libraries, particularly university and other academic libraries, you may see that instead of the author's last name, there is a letter and mix of numbers. These are known as Cutter numbers. If you are borrowing materials from another library and have questions about how to read Cutter numbers, please speak to Ms. Antchak.