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Dewey Classification System

Subject Classification

The classification schemes the Library uses to arrange the material on the shelves are designed to group together as much as possible (within the constraints of a simple linear order) related topics within the same discipline.

For many purposes this offers a meaningful arrangement which facilitates browsing along the shelves and the retrieval of relevant documents.


The main classification system used by the EUI Library is the Dewey Decimal Classification.

Many revisions of this scheme have been published which restructured or re-articulated various parts of the classification or introduced entirely new parts as required by an ever evolving body of documented knowledge.

1997 Changes

In 1997 the Library started using the latest revision of the Dewey Decimal Classification (21st edition, published 1996). This has had a few consequences of which users should be aware.

In all cases where there is a precise shelf address for the book they are looking for (e.g. LIB 321.04094 LOS), the number indicates exactly where the book is on the shelves and nothing changes in they way it is then retrieved by the user.

However, when browsing along the shelves in the Library or through the shelf index in the catalogue will users sometimes see a discontinuity in the numbering between older and newer books within a topic or discipline.

For example, books on political parties acquired by the Library before 1st January 1997 are located at 329 (the Dewey number for political parties in the 18th edition. Books on political parties acquired after that date are classified at 324 which is where the 21st edition places them.

Further details about important number changes are contained in the detailed accounts of the classification numbers for each subject area:

Dewey Decimal Classification Scheme for Philosophy (21st edition)

The 19th century origins of the Dewey Decimal Classification (DDC) scheme are revealed in the section heading for 100, even in the 21st edition used by the EUI Library: 'Philosophy, Paranormal Phenomenon, Psychology'.

Fortunately, by the standards of the rest of the DDC, the internal structure of this section is simple and relatively stable between editions: every decimal step contains a major category of philosophy and within this, as always in Dewey, more precise sub-categories.

Readers should also be aware that the philosophical aspects of the other main Dewey subject categories are classified at the beginning of that category. Political philosophy in general, for example, will be found at 320.01.

Below are the main categories and sub-categories used in this library.


  • 100 General philosophy: somewhat of a catch-all category
  • 103 Dictionaries and encyclopaedias of philosophy
  • 109 General histories of philosophy
  • 120-129 Epistemology, causation, humankind
  • 130-139 Paranormal phenomenon (includes phrenology at 139)
  • 140-149 Specific philosophical schools and viewpoints: contains the following vague and outdated schools: Idealism, Bergsonism, Humanism, Sensationalism, Pantheism, Dogmatism, Syncretism
  • 150-159 Psychology : includes the main psychological and psychoanalytical schools and well as materials on conscious and unconscious metnal processes
  • 160-169 Logic: induction, deduction, fallacies, syllogisms, hypotheses, argumentation, analogy
  • 170-179 Ethics: an important category for the EUI; includes ethical systems, political ethics, bioethics, professional ethics
  • 180-189 Ancient, medieval and Oriental philosophy
  • 190 Modern Western philosophy: another important category for the EUI. If the author is deemed by history or the current classifier to be sufficiently important, a sub-section is created by joining the first three letters of the philosopher's name to the classification. Works about that philosopher are then classified in that section. Within these categories, books are arranged alphabetically by author. So a book by Michel Foucault will be found at 194-FOU FOU; a book about Foucault by Gilles Deleuze will be found at 194-FOU DEL. If Foucault had ever written a book about Gilles Deleuze, it would be found at 194-DEL FOU. If Deleuze and Foucault had ever written a book together, it would be difficult to know where to classify it. Probably in 194 (General French Philosophy)
  • 191 United States and Canada
  • 192 The British Isles includes famous Scottish and Irish philosphers
  • 193 Germany and Austria
  • 194 France
  • 195 Italy
  • 196 Spain and Portugal
  • 198 Scandinavia

Dewey Decimal Classification Scheme for Sociology (21st edition)

Significant changes between the 18th and 21st editions of Dewey (those previously - before Jan. 1st 1997 - and currently in use in the EUI Library) occurred in the subject numbers dealing with Sociology (300-309).

The most obvious difference is that in the 18th edition the numbers 302-308 were unassigned (not used). Books dealing with the topics listed below under these numbers were classified in sub-categories of the section 301. So human communication previously classified at 301.14 has now moved to 302.2.

This means that recent books in sociology will generally be found in the more transparent groupings listed below. Although this new arrangement leads to a sequence break in our collections, it does not involve sequence confusion (where a subject number has two completely different meanings in the 18th and 21st editions).

The broad outlines of 300-319 are given below along with some sub-categories that are important for the EUI Library. These specific numbers can be used in classification number searches on our on-line catalogue to retrieve recent material about the subject covered.


300 The Social Sciences in General

300.1    Philosophy and Theory

300.72  Research Methods

301 Sociology and Anthropology

301.01  Social Theory

N.B.  Cultural Anthropology now in 306


302 Social Interaction 


302.2  Communication (including media)

302.4  Social Interaction Between Groups


303 Social Processes

303.4  Social Change (incl. globalisation)

303.6  Conflict (incl. war and revolution)


304 Factors Affecting Social Behaviour

304.23  Sociology of Time

304.8  Migration


305 Social Groups

305.2  Age Groups

305.3  Men and Women

305.4  Women

305.5  Social Classes

305.6  Religious Groups

305.7  Language Groups

305.8  Racial, Ethnic, National Groups

305.9  Occupational and Miscellaneous Groups


306 Culture and Institutions

306.1  Subcultures

306.2  Political Sociology

306.3  Economic Sociology

306.4  Sociology of specific aspects of culture (incl. language, science, art, recreation)

306.6  Sociology of religion

306.7  Sociology of sexual matters

306.8  Sociology of marriage and the family

306.9  Sociology of death


307 Communities

307.1  Planning and development (incl. regional planning)

307. 76  Urban communities (i.e. cities)

308 & 309 Not used ('assigned') in the 21st edition of Dewey


310-319 Collections of General Statistics:

not in use in the EUI Library which has a separate

Statistics collection and Statistics Classification Scheme.  


Dewey Decimal Classification Scheme for Political Science (21st Edition)

320-329 are the numbers assigned by Dewey to 'Political Science (Politics and Government)'. Some changes have occurred between the 18th edition, in use in the Library until the end of 1996, and the 21st which has been used since 1997 to classify all new acquisitions.

The most significant of these changes is the suppression of 329, formerly used for literature on political parties, and its incorporation into 324 which was previously dedicated to voters and elections but has now become a catch-all section entitled 'The political process'.

Users should be aware that some numbers in this section can have different classifcatory meanings depending on whether the book was classified before or after 1st Jan. 1997. Strangely enough, the 21st edition still retains 326 as the number for slavery and emancipation. Below is a list of the main sub-sections in 320 along with the most frequently used Dewey numbers in the EUI Library.


320 Political Science

320.01  Political Philosophy

320.1  The State (incl. 320.101 - philosophy and theory of the state)

320.3  Comparative Government

320.5  Political Ideologies (incl. liberalism, conservatism, socialism, fascism and communism)

320.54  Nationalism

320.6  Policy-making

320.8  Local Government


321 Systems of Governments and States

321.04094  European Union

321.8  Democracy

321.9  Authoritarian Government


322 Relation of the State to Organized Groups and their Members

322  Neo-corporatism

322.1  Relgious Organizations and Groups

322.2  Labour Movements and Groups

322.3  Business and Industry

322.4  Political Action Groups (incl. pressure groups, protest groups, reform movements)

322.5  Armed Services


323 Civil and Political Rights

323.1  Rights of Minority Groups

323.3  Human Rights

323.6  Citizenship


324 The Political Process

324  Voting

324.2  Political Parties

324.24 -.9  Political Parties by country / region (individually

and by ideology) 


325 International Migration and Colonization

325.1  Immigration

325.2  Emigration

325.21  Refugees

325.3  Colonization

325.4  European Immigration


326 Slavery and Emancipation


327 International Relations

327.101  Theory of International Relations

327.2  Diplomacy

327.4  European Foreign Policy

327.4 - .9  Foreign Policies of Individual Countries


328 The Legislative Process

328  Parliaments and Legislatures

328.3  Specific topics (incl. Bicameralism, members, powers and privileges, lobbying)

328.4  European Parliament

328.4 -.9  Legislatures in individual countries


329 Political Parties (until 1997)

329 N.B. No longer used - see 324

329.02  Party Systems

329.02094  Poltical Parties in Europe

329.02094 - 9  Political Parties by Country


The classifications listed above are the principal Dewey numbers of interest to social and political scientists but please also note the following sections: 

330 Economics (incl. Trades Unions, Socialism, and Development)

350 Public Administration and Military Science (incl. War and Defence)

360Social Problems (incl. The Welfare State, Criminology

380 Commerce, Communications, Transportation (incl. International Trade)

400 Language (incl. Theory of Language and Discourse Analysis)

500 Natural Sciences and Mathematics (incl. Philosophy of Science and Statistical Theory)

800 Literature (incl. Literary Theory and Classical Literature)

900 History (incl. Philosophy of History)


Classifications of other collections of interest to social and political scientists

  • The European Documentation Centre stocks publications of the European institutions and has its own classification scheme.
  • The Statistical Data Collection is organised according to a UN-Eurostat classification system.

Page last updated on 16 February 2024

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