The Dewey Decimal Classification (DDC, also called the Dewey Decimal System) is a proprietary system of library classification developed by Melvil Dewey in 1876, and has since then been greatly modified and expanded through twenty-two major revisions, the most recent in 2004. Proprietary indicates that a party, or proprietor, exercises private ownership, control or use over an item of property, usually to the exclusion of other parties. ... Library classification forms part of the field of library and information science. ... Melvil Dewey (December 10, 1851–December 26, 1931) was the inventor of the Dewey Decimal Classification system for library classification. ...

How it works

The DDC attempts to organize all knowledge into ten main classes. The ten main classes are then further subdivided. Each main class has ten divisions, and each division has ten sections. Hence the system can be summarized in 10 main classes, 100 divisions and 1000 sections. DDC's advantage in choosing decimals for its categories allows it to be both purely numerical and infinitely hierarchical. For other uses, see Decimal (disambiguation). ...

It also uses some aspects of a faceted classification scheme, combining elements from different parts of the structure to construct a number representing the subject content (often combining two subject elements with linking numbers and geographical and temporal elements) and form of an item rather than drawing upon a list containing each class and its meaning. A faceted classification system allows the assignment of multiple classifications to an object, allowing searching and browsing of related information through several classes. ...

Except for general works and fiction, works are classified principally by subject, with extensions for subject relationships, place, time or type of material, producing classification numbers of no less than three digits but otherwise of indeterminate length with a decimal point before the fourth digit, where present (e.g. 330 for economics + 9 for geographic treatment + 4 for Europe = 330.94 European economy; 973 for United States + 05 form division for periodicals = 973.05, periodicals concerning the United States generally). For other uses, see Fiction (disambiguation). ... Face-to-face trading interactions on the New York Stock Exchange trading floor. ... For other uses, see Europe (disambiguation). ... This article is about the magazine as a published medium. ...

Books are placed on the shelf in increasing numerical order; the whole number to the left of the decimal is in counting order, while the digits to the right of the decimal are compared one digit at a time, with a blank coming before zero. (Example: 050, 220, 330.973, 331 etc.) When two books have the same subject, and therefore the same classification number, the second line of the call number, which usually has the first letter or first several letters of the author's last name (or the title if there is no identifiable author), is placed in alphabetical order. The whole numbers are the nonnegative integers (0, 1, 2, 3, ...) The set of all whole numbers is represented by the symbol = {0, 1, 2, 3, ...} Algebraically, the elements of form a commutative monoid under addition (with identity element zero), and under multiplication (with identity element one). ...

It is a common misconception that all books in the DDC are non-fiction. The DDC has a number for all books, including those that generally become their own section of fiction. If DDC rules are strictly followed, American fiction is classified in 813. Most libraries create a separate fiction section to allow shelving fiction in a more generalised fashion than Dewey provides for, or to avoid the space that would be taken up in the 800s.

DDC compared to other classification systems

For more details on this topic, see Comparison of Dewey and Library of Congress subject classification.

DDC's numbers formed the basis of the more expressive but complex Universal Decimal Classification, which combines the basic Dewey numbers with selected punctuation marks (comma, colon, parentheses etc.). Besides its frequent revision, DDC's main advantage over its chief American rival—the Library of Congress Classification system developed shortly afterward—is its simplicity. Thanks to the use of pure notation, a mnemonics system and a hierarchical decimal place system, it is generally easier to use for most users. This is a comparison chart showing how the Dewey Decimal System and the Library of Congress organize materials by subject for the purpose of assigning call numbers. ... The Universal Decimal Classification is a system of library classification developed by the Belgian bibliographers Paul Otlet and Henri la Fontaine at the end of the 19th century. ... Library of Congress reading room The Library of Congress Classification (LCC) is a system of library classification developed by the Library of Congress. ...

DDC and UDC are also more flexible than Library of Congress Classification because of greater use of facets (via auxiliary tables) while Library of Congress Classification is almost totally enumerative. Library of Congress reading room The Library of Congress Classification (LCC) is a system of library classification developed by the Library of Congress. ...

On the flip side, DDC's decimal system means that it is less hospitable to the addition of new subjects, as opposed to Library of Congress Classification which has 21 classes at the top level. Another side effect of this is that DDC notations can be much longer compared to the equivalent class in other classification systems.

Another disadvantage of DDC is that it was developed in the 19th century, by essentially one man, and was built on a top down approach to classify all human knowledge which made it difficult to adapt to changing fields of knowledge. In contrast, the Library of Congress Classification system was developed based mainly on the idea of literary warrant; classes were added (by individual experts in each area) only when needed for works owned by the Library of Congress. As a result, while the Library of Congress Classification system was able to incorporate changes and additions of new branches of knowledge, particularly in the fields of engineering and computer science (the greater hospitability of the Library of Congress Classification was also a factor), DDC has been criticized for being inadequate for covering those areas. As a result, most major academic libraries in the US do not use the DDC because the classification of works in those areas is not specific enough.

The Library of Congress Classification system is not without problems; because each area is developed by an expert according to demands of cataloging, there is little consistency. It is also highly US-centric (more so than DDC) because of the nature of the system, and compared to DDC and UDC it has been translated into far fewer languages.

Ownership and administration

The Online Computer Library Center of Dublin, Ohio, acquired the trademark and any copyrights associated with the Dewey Decimal System when it bought Forest Press in 1988. OCLC maintains the classification system and publishes new editions of the system. The work of assigning a DDC number to each newly published book is performed by a division of the Library of Congress, whose recommended assignments are either accepted or rejected by the OCLC after review by an advisory board; to date all have been accepted. Founded in 1967, OCLC Online Computer Library Center is a nonprofit, membership, computer library service and research organization dedicated to the public purposes of furthering access to the worlds information and reducing information costs. ... Motto: Its greener in Dublin. ...

In September 2003, the OCLC sued the Library Hotel for trademark infringement. The settlement was that the OCLC would allow the Library Hotel to use the system in its hotel and marketing. In exchange, the Hotel would acknowledge the Center's ownership of the trademark and make a donation to a nonprofit organization promoting reading and literacy among children. The Library Hotel is a 60-room boutique hotel in New York City, located at 299 Madison Avenue (at 41st Street), near the New York Public Library, Bryant Park, and Grand Central Terminal. ...

Classes

Main article: List of Dewey Decimal classes

The system is made up of ten main classes or categories, each divided into ten secondary classes or subcategories, each having ten subdivisions of its own. The Dewey Decimal System of library classification is made up of ten main classes or categories, each divided into ten secondary classes or subcategories, each having ten subdivisions. ...

• 000 – Computer science, information, and general works
• 100 – Philosophy and psychology
• 200 – Religion
• 300 – Social sciences
• 400 – Language
• 500 – Science
• 600 – Technology
• 700 – Arts and recreation
• 800 – Literature
• 900 – History and geography

Computer science, or computing science, is the study of the theoretical foundations of information and computation and their implementation and application in computer systems. ... The ASCII codes for the word Wikipedia represented in binary, the numeral system most commonly used for encoding computer information. ... For other uses, see Philosophy (disambiguation). ... Psychological science redirects here. ... The social sciences are a group of academic disciplines that study human aspects of the world. ... A magnet levitating above a high-temperature superconductor demonstrates the Meissner effect. ... By the mid 20th century humans had achieved a mastery of technology sufficient to leave the surface of the Earth for the first time and explore space. ... The Arts is a broad subdivision of culture, comprised of many expressive disciplines. ... “Fun” redirects here. ... For other uses, see Literature (disambiguation). ... This article is about the study of the past in human terms. ...

See also

• Nippon Decimal Classification
• Chinese Library Classification
• Colon classification
• Comparison of Dewey and Library of Congress subject classification
• Harvard-Yenching Classification
• The Library Hotel
• Library of Congress Classification
• Universal Decimal Classification
• Hotel Denouement, a fictional hotel classified using the Dewey Decimal System in Lemony Snicket's A Series of Unfortunate Events
• ACM Computing Classification System

The Nippon Decimal Classification (NDC, also called the Nippon Decimal System) is a system of library classification developed for mainly Chinese and Japanese language books maintained by the Japan Library Association since 1956. ... The Chinese Library Classification (CLC), also known as Classification for Chinese Libraries (CCL) is a library classification that is currently widely used in almost all of the libraries of primary and secondary schools, academic institutions, colleges, universities as well as public libraries throughout Mainland China in the Peoples Republic... Colon classification (CC) is a system of library classification developed by S. R. Ranganathan. ... This is a comparison chart showing how the Dewey Decimal System and the Library of Congress organize materials by subject for the purpose of assigning call numbers. ... Alfred Kaiming Chiu (1898-1977) was a pioneer of establishing a library classification system for Chinese language materials in the United States of America. ... The Library Hotel is a 60-room boutique hotel in New York City, located at 299 Madison Avenue (at 41st Street), near the New York Public Library, Bryant Park, and Grand Central Terminal. ... Library of Congress reading room The Library of Congress Classification (LCC) is a system of library classification developed by the Library of Congress. ... The Universal Decimal Classification is a system of library classification developed by the Belgian bibliographers Paul Otlet and Henri la Fontaine at the end of the 19th century. ... Many businesses appear in the childrens book series A Series of Unfortunate Events by Lemony Snicket. ... For other uses, see Hotel (disambiguation). ... Lemony Snicket is a pseudonym used by author Daniel Handler in his book series A Series of Unfortunate Events, as well as a character in that series. ... This article is about the book series. ... The ACM Computing Classification System is a subject classification system for computer science devised by the Association for Computing Machinery. ...

External links

• Complete list of Dewey Decimal Classes
• OCLC's Dewey Decimal website
• Full text of A Classification and Subject Index for Cataloguing and Arranging the Books and Pamphlets of a Library (Dewey Decimal Classification) (1876) from Project Gutenberg
• "What's so great about the Dewey Decimal System?" at Straight Dope, 31 January 2006
• A History of the D.D.C. System and its Creator Melville Dewey by University of British Columbia's mission, the School of Library, Archival and Information Studies
• A Dewey Decimal System Tutorial by the Illinois State Library, funded by the Gates Foundation
• An annotated bibliography on Library Classification and Subject Approaches to Information by Salman Haider, Librarian (Cataloging), US Library of Congress, New Delhi Overseas Office