Features of Dewey Decimal System
The Dewey Decimal Classification (DDC) is the first of the important library classification schemes, and is still the most widely used scheme. It has ten main classes (000 to 900 - known as the ‘first schedule’ or the ‘first summary’). These are further subdivided into units of ten (010-990 - known as the ‘second schedule’). These are then subdivided by ten (so that the one-thousand division from 001 to 999 is known as the ‘third schedule’). So without even using the famous “Decimal Point”, there are 1000 numbers in the System.
10 Main Classes (first schedule or first summary)
100 Divisions (second schedule or second summary)
1000 Sections (third schedule or third summary)
The Major Features of DDC
DDC is published in a number of ways.
· Printed volumes. The full edition is currently in 4 volumes
· Abridged edition in one volume (often used in school libraries)
· On-line version, known as WebDewey
The Tables
These are never used to start a classification number, but can be added to an existing schedule number. Table numbers are indicated in the Index by the use of the letter ‘T’ as a prefix, such as: Women
Women T1-082
There are six numbered Tables:
T1 Standard Subdivisions (such as ‘Encyclopedia’, or ‘Periodical’)
T2 Geographic areas, Historical periods, Biography
T3 Literatures and literary form
T4 Individual languages & language families
T5 Racial, Ethnic and National groups
T6 Languages
The Schedules
The Schedule numbers include the start (or ‘base’ number) of each DDC number. They range from 000 to 999.
The ten main classes are:
000 Generalities
100 Philosophy, Psychology
200 Religion
300 Social sciences
400 Languages
500 Pure sciences and Mathematics
600 Applied sciences and Technology
700 The arts.
800 Literature
900 Geography, and History.
Two rules regarding schedule numbers:
· Schedule numbers are never less than three digits long, and
· a schedule number must never end in zero anywhere to the right of the decimal point.
For example, use 512.31 NOT 512.310
The Relative Index
This is an alphabetical index to Schedule and Table numbers.
There is also a manual which contains advice on choosing between two likely numbers .
The usual order of approach when classifying is to:
Search for the number in the relative index
The instructions are not found in the index, so you should never classify from the Index alone, in case you miss them. In WebDewey use the number when it is in BOLD face
Use the Auxiliary Tables (Table 1) if you want to add to the existing number
In “borderline” cases, go back to the Manual for advice about difficult classification areas, or to interpret “what fits where” when you are deciding between two or more likely numbers.
Since the classes govern the overall structure, once you have decided what the work is about, determine the class in which the main subject belongs.
eg, identify all the secondary aspects of the work, and then the importance of each of these aspects.
For example,
Censorship in Iran: an encyclopaedia
Main subject: Censorship
Discipline (class): Social sciences (300)
Secondary aspects: Iran
Encyclopaedia
Order of importance: 1 - Censorship
2 - Iran
3 - Encyclopaedia
Another useful tool to help with classifying an item is to remember <SAPT>. This is:
SUBJECT-ASPECT-PLACE-TIME
10 Main Classes (first schedule or first summary)
100 Divisions (second schedule or second summary)
1000 Sections (third schedule or third summary)
The Major Features of DDC
DDC is published in a number of ways.
· Printed volumes. The full edition is currently in 4 volumes
· Abridged edition in one volume (often used in school libraries)
· On-line version, known as WebDewey
The Tables
These are never used to start a classification number, but can be added to an existing schedule number. Table numbers are indicated in the Index by the use of the letter ‘T’ as a prefix, such as: Women
Women T1-082
There are six numbered Tables:
T1 Standard Subdivisions (such as ‘Encyclopedia’, or ‘Periodical’)
T2 Geographic areas, Historical periods, Biography
T3 Literatures and literary form
T4 Individual languages & language families
T5 Racial, Ethnic and National groups
T6 Languages
The Schedules
The Schedule numbers include the start (or ‘base’ number) of each DDC number. They range from 000 to 999.
The ten main classes are:
000 Generalities
100 Philosophy, Psychology
200 Religion
300 Social sciences
400 Languages
500 Pure sciences and Mathematics
600 Applied sciences and Technology
700 The arts.
800 Literature
900 Geography, and History.
Two rules regarding schedule numbers:
· Schedule numbers are never less than three digits long, and
· a schedule number must never end in zero anywhere to the right of the decimal point.
For example, use 512.31 NOT 512.310
The Relative Index
This is an alphabetical index to Schedule and Table numbers.
There is also a manual which contains advice on choosing between two likely numbers .
The usual order of approach when classifying is to:
Search for the number in the relative index
The instructions are not found in the index, so you should never classify from the Index alone, in case you miss them. In WebDewey use the number when it is in BOLD face
Use the Auxiliary Tables (Table 1) if you want to add to the existing number
In “borderline” cases, go back to the Manual for advice about difficult classification areas, or to interpret “what fits where” when you are deciding between two or more likely numbers.
Since the classes govern the overall structure, once you have decided what the work is about, determine the class in which the main subject belongs.
eg, identify all the secondary aspects of the work, and then the importance of each of these aspects.
For example,
Censorship in Iran: an encyclopaedia
Main subject: Censorship
Discipline (class): Social sciences (300)
Secondary aspects: Iran
Encyclopaedia
Order of importance: 1 - Censorship
2 - Iran
3 - Encyclopaedia
Another useful tool to help with classifying an item is to remember <SAPT>. This is:
SUBJECT-ASPECT-PLACE-TIME