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Library of Congress classification scheme

The Library arranges its collections of books and bound periodicals according to the Library of Congress Classification Scheme. Each book has a class mark consisting of letters and numbers which indicate its subject and determine where it is filed on the shelf.

The code usually begins with two letters

  • The first letter represents the broad subject. For example, all D books (History) are on the Second Floor.
  • The second letter specifies a narrower subject area within the broad category: within History (D), DA stands for British History.
  • The next part of the class mark is a number, which gives a more precise definition of subject matter. Within a subject section, books are filed numerically, so DA 84 comes before DA 86 which comes before DA 226.
  • The final part of the class mark refers to the author's name. It normally consists of a letter and a number. This part is filed in alphabetical order by letter, then by number in a decimal sequence, i.e. DA 84.C3 precedes DA 84.C35 which precedes DA 84.C4

In practice, class marks may be more complex, with extra letters and numbers giving a more precise definition of subject matter. In each case, read down the class mark, taking each element separated by a full stop as a separate unit.

The following list gives a more detailed breakdown of subjects and their class marks

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z




Anatomy QM Mezzanine
Ancient history DE - DG Second Floor
Anglo-Saxon language and literature PE First Floor
Anthropology GF - GT Second Floor
- theory and methods CC Second Floor
- specific countries D - F Second Floor
Architecture NA First Floor
Art N-NX First Floor
Astronomy QB Mezzanine
Atlases REF 5 Ground Floor
Biblical studies BS First Floor
Bibliography Z Rare Books Reading Room
Biochemistry QP Mezzanine
Biology QH Mezzanine
Botany QK Mezzanine
Cambridge local history
- county DA 670.C2 Second Floor
- city DA 690.C2 Second Floor
Cambridge University LF First Floor
Celtic language and literature PB First Floor
Chemical engineering TN - TR Second Floor
Chemistry QD Mezzanine
Church history BR & BX First Floor
Civil engineering TA - TH Second Floor
Classics PA First Floor
Computer science QA Mezzanine
Constitutional history JN Second Floor
Criminology HV Third Floor
Dictionaries REF 2 - 4 Ground Floor
Earth sciences QE Mezzanine
Economic history HC - HD Second Floor
Economics HB - HJ Second Floor
Education L First Floor
Encyclopaedias REF 1 Ground Floor
- Chemical TN - TR Second Floor
- Civil TA - TH Second Floor
- Electrical TK Second Floor
- Mechanical TJ - TL Second Floor
English language PE First Floor
English literature PR First Floor
Environmental studies GE Second Floor
European history D - DR Second Floor
Film studies PN First Floor
French language PC First Floor
French literature PQ First Floor
Gender studies HQ Second Floor
- Human GF Second Floor
- Physical G - GC Second Floor
Geology QE Mezzanine
German language PD First Floor
German literature PT First Floor
Greek language & literature PA First Floor
-African DT Second Floor
-American E - F Second Floor
-Asian DS Second Floor
-British DA Second Floor
-European D - DR Second Floor
-Russian DK Second Floor
History & Philosophy of Science Q Mezzanine
International relations JZ Second Floor
(also see the country) D - F Second Floor
Italian language PC First Floor
Italian literature PC First Floor
Latin language & literature PA First Floor
Law K Third Floor
Linguistics (general) P First Floor
Linguistics (individual languages) PA - PM First Floor
Management studies HD & T Second Floor
Maths (pure & applied) QA Mezzanine
Mechanical engineering TJ - TL Second Floor
Medicine R Second Floor
Microbiology QR Mezzanine
-Scores M First Floor
-Books ML First Floor
-CDs & Videos AV collection First Floor
Natural history QH Mezzanine
Norse language & literature PD First Floor
Oriental languages & literature PJ - PM First Floor
Philosophy B First Floor
Physics QC Mezzanine
Physiology QP Mezzanine
-Political science and theory JA & JC Second Floor
-Political administration JF-JS Second Floor
Psychology BF First Floor
Reference books REF Ground Floor
Russian language & literature PG First Floor
Social history HN Second Floor
Social welfare HV Third Floor
Sociology HM - HX Second Floor
Spanish language PC First Floor
Spanish literature PQ First Floor
Theology BL - BX First Floor
Veterinary medicine S Second Floor
Videos AV collection First Floor
Women's studies HQ Second Floor
Zoology QL Mezzanine