How the Dewey Decimal Classification System Works 

The DDC works by organizing knowledge by discipline rather than by subject. There are ten different disciplines or main classes that contain subjects within them. The disciplines, or main classes, are:

000-099 Generalities

100-199 Philosophy, paranormal phenomena, psychology

200-299 Religion

300-399 Social sciences

400-499 Language

500-599 Natural sciences and mathematics

600-699 Technology (Applied sciences)

700-799 The Arts: Fine and decorative arts

800-899 Literature (Belles letters) and rhetoric

900-999 Geography, history, and auxiliary disciplines ¹

Within Each main class there are ten divisions:

For example, the discipline of Social sciences 300-399:

300-309 Social sciences

310-319 Collections of general statistics

320-329 Political science

330-339 Economics

340-349 Law

350-359 Public administration & military science

360-369 Social problems & services: association

370-379 Education

380-389 Commerce, communications, transportations

390-399 Customs, etiquette, folklore ²

And, within each division there are ten sections:

For example, the division of 330-339:

330 Economics

331 Labor economics

332 Financial economics

333 Economics of land & energy

334 Cooperatives

335 Socialism & related systems

336 Public finance

337 International economics

338 Production

339 Macroeconomics & related topics ³

Dewey Decimal classification numbers are set up so that the first 3 digits followed by a period and then a second string of 3 numbers will be unbroken, all digits following this will be divided into groups of three, as shown by the following:

398.245 296 33

300 – Social Sciences

398 – Folklore

398.2 – Folk Literature

398.24 – Tales and Lore of Plants and Animals

398.245 – Animals

398.245 2 – Real Animals

398.245 29 – Specific Animals

398.245 296 33 – Suidae (Pigs, Swine)

As a result of the structure of the DDC subjects may re-appear repeatedly in the schedules and in different formats within the various disciplines. For example, Copper [in the Relative Index, Vol 4.] has several subdivisions that address numerous aspects of it in its cataloguing. They also make it easier to identify an aspect of a larger topic:

Copper

applied nutrition                   613.285

architectural construction     721.044 73

biochemistry                        572.518

humans                          612.015 24

etc.

Consistently, many aspects of subjects are expanded upon in this way in order to provide as detailed a guide to cataloguing different works as possible. 

The manner in which the DDC is set up will create tree like structures so that each level is more and more precise, and that numbers of the same level will be subordinate to the notation one digit before it:

Example:  

381.3 International commerce (Domestic trade): Commercial policy

381.32 Consumer movements

381.33 Consumer information

381.34 Consumer protection

All three of the previous example (381.32-381.34), are subordinate to 381.3. Note also that the structure and notation itself will help to lead the cataloguer to the definition that s/he seeks.

There are a number of rules within the DDC that assist in the placement of works within the different disciplines:

1. Under the rule of application, the rule that takes precedence over others, works that deal with interrelated subjects should be placed under the subject that is being acted upon.

2. In a work that has 2 subjects class material under the subject that receives more than 50 % of the attention in the writing.

3. Under the first of 2 rule you classify a work, assuming both subjects receive equal treatment, with the one that comes first in the schedules.

Ex: A book about taking care of domestic cats, and fish within aquariums.

636.82 Short haired cats

639.34 Fish culture in aquariums

In the above example cats come before fish, and so the book would go under cats.

4. The rule of three indicates that if there are 3 or more subjects then, provided they all receive equal treatment, place them under a higher, less specific number in the schedule that covers all of them.

Ex: A book about keeping different types of dogs.

636.72 Nonsporting dogs

636.73 Working and herding dogs

636.75 Sporting dogs, hounds, terriers

In this example this work would have been kept under: 636.7 Dogs

5. The rule of zero suggests that, when given a choice, 1-9 should be chosen over 0:

Ex: 631 over 630

And, that, when given a choice, 0 should be chosen if the alternate contains a 00:

Ex: 658.403 01 over 658.403 001

If in doubt, a cataloguer should recall and use the table of last resort, and in descending order without another rule to refer too:

1. Kinds of things

2. Parts of things

3. Materials from which things, kinds or parts are made

4. Properties of things, kinds, parts, or materials

5. Processes within things, kinds, parts, or materials

6. Operations upon things, kinds, parts, or materials

7. Instrumentalities for performing such operations ⁴

The implication of this list is the choice of things over processes.

DDC 21 is a very expansive set of material spanning 4 volumes, and there will be times when a cataloguer will need to have 3 or even all 4 of the books open in order to catalogue a work.

Structure of the DDC 

The overall break down, of the most important main sections in the 4 volumes of the DDC are as follows:

Volume 1

Preface

New features of [ex] DDC 21

Introduction to DDC 21

Glossary

Table 1. Standard subdivisions

Table 2. Geographic Areas, Historical Periods, Persons

Table 3. Subdivisions for the Arts, for Individual Literatures, for Specific Literary Forms

Table 3A. Subdivisions for Works by or About Individual Authors

Table 3B. Subdivisions for Works by or About  More than One Author

Table 3C. Notation to be Added Where Instructed in Table 3B, 700.4, 791.4, 808-809

Table 4. Subdivisions of Industrial Languages and Language Families

Table 5. Racial, Ethnic, National Groups

Table 6. Languages

Table 7. Groups of Persons

Relocations and Reductions

Comparative Tables

Equivalence Tables

Reused Numbers

Volume 2

             Schedules 000-599

Volume 3

             Schedules 600-999

Volume 4  

         Relative Index. [Subjects are arranged alphabetically to take the searcher to the correct discipline classification number.]

Manual. [The manual will often provide insight on how to classify    in complicated areas. And you will be directed to it from the schedules.]⁵

To classify material it is often best to begin with the CIP (Cataloging in Publication) data found on the verso page of a work, and to see of a suggested DDC or LC call number is already given. If there is no CIP and no record can be found pre-made within catalogs like the Library of Congress, the National Library of Canada, or the Online Computer Library Catalogue (OCLC) then it will be necessary to formulate a call number. Within the DDC this begins with formulating a statement of about-ness.

            For example:

Author: John Dawes

Title: Complete Encyclopedia of the Freshwater Aquarium

Subject Statement: A guide to setting up and maintaining a freshwater aquarium at home, and how to choose a proper selection of freshwater fish for your needs.

Now that a statement has been given go to the relative index in volume 4 to find the best choice of subject which would be one of the following two choices:

Aquariums             597.073

      fish culture       639.34

Given that the work is dealing largely with aquariums and freshwater fish the better choice would be ‘fish culture,’ and from here you would go to volume 3 for the schedules dealing with DDC numbers 600-999.

Within the schedules under the suitable entry it indicates the following:

639

      .34   Fish culture in aquariums

              Class here freshwater aquariums, home aquariums

              Class interdisciplinary works on aquariums in 597.073

It is then clear that the proper choice for call number for this work would be 639.34 followed by a suitable cutter number if that is the procedure followed by your library.

There will also be occasions where a more complicated form of cataloging will need to be done. With regards to literature, history, geography, and many other works that utilize the manual, the tables, or both there are rules to remember.

First: Always read all of the notes involved and take care not to proceed too quickly.

Second: Try to verify your work if possible by going to OPACs of already existing catalogs and doing searches under the numbers you created. This will tell you if you are in the ballpark for a proper classification.

Third: If in doubt seek a second opinion, or do it over again.

There are too many rules and notes to cover with regards to number building to give a complete rundown of the processes involved; however, one example of a simple breakdown could be very useful. Take for example the following:

Author: Anais Nin

Title: Fire: From “A Journal of Love”: The Unexpurgated Diary of Anais Nin, 1934-1937

Anais Nin primarily wrote in North America, and her work would be classified under a work of literature so a DDC number would be in the range between 811-818.

811-818    Specific forms of American literature in English

From here the schedules redirect you to table 3.

Initially within table 3 the classifier must choose one of three sub-tables: 3-A – 3-C:

Table 3-A for the description, critical appraisal, biography, single or collected works of an individual author

Table 3-B for description, critical appraisal, biography, collected works of two or more authors; also for rhetoric in specific literary forms

Table 3-C for additional elements used in number building within Table 3-B and as instructed in 700.4, 791.4, 808-809

In this case there is only one primary author, and so Table 3-A would be consulted. Initially consulting ‘–1-8 Specific forms’, the searcher would find that the best form for this work would be under ‘Miscellaneous writings –8,’ as this form from the list best describes this work.

Next, going to ‘-8’, it gives further instructions to go back to the schedules in volume 3 for additional choices in the act of number building. However, for the moment the number built is ‘818.’ The searcher is now directed to: 

810.1-818 Subdivisions of American literature in English

Under the period tables there is a possibility under:

For United States

52    1900-1945

Following the instructions starting under Table 3-A we are instructed to return, after choosing the period, to choose from ‘-81-89 Specific periods.’

The best choice under this list is:

      03              Diaries, journals, notebooks, reminiscences

The resulting call number is:

818.5203 Literature written between 1900-1945: Diaries, journals,         notebooks, reminiscences.

There are further instructions beyond the ‘03’ to refer to the manual for additional clarification, but in this case it is merely for a better understanding of why this particular choice is correct. Number building can be extremely complicated and one of the best ways to accomplish it if necessary is to proceed slowly and to read all of the instructions that are given to you. The previous example is a simplistic example of number building, but it illustrates that a great deal of care and precision has gone into constructing the DDC and in making it work very accurately.

_____________________________________________________________

1.       Melvil Dewey, DDC 21: Dewey Decimal Classification and Relative Index, vol. 4, Introduction & Tables, ed. Joan S. Mitchell, Julianne Beall, Winton E. Matthews, Gregory R. New, Albany, New York: Forest Press, 1996),  xxxiii.

2.       Melvil Dewey, DDC 21: Dewey Decimal Classification and Relative Index, vol. 2, Schedules 000-599, ed. Joan S. Mitchell, Julianne Beall, Winton E. Matthews, Gregory R. New, Albany, New York: Forest Press, 1996),  x.

3.       Ibid. xiv.

4.      Ibid., Vol. 1, xxxviii. 

5.      Ibid., vii-ix.

PART  1
SECTION 1
SECTION 2
SECTION 3      SECTION 4

PART  2
SECTION 1
SECTION 2
SECTION 3      SECTION 4

PART  3
SECTION 1
SECTION 2

CONCLUSION AND BIBLIOGRAPHY