Used by the Library Of Congress (Washington DC, USA) is an alpha-numeric code with the principal categories represented by a 2 letter code.

* A General Works
** AE Encyclopedias
** AI Indexes

* B  Philosophy, Psychology, Religion
** B-BD Philosophy
** BF Psychology
** BL-BX Mythology, Religion

* C Auxiliary Sciences to History
** CB History of Civilisation
** CC Archaeology 
** CS Genealogy
** CT Biography 

* D History (outside of North America)
** D Ancient and World History 
** DA England (Great Britian)
** DC France 
** DD Germany
** DS Asia 
** DT Africa   

* E-F History: North America
** E 1-143 America (general)
** E 151-857 United States (general)
** F 1-957 U.S. ( states and local)
** F 1001-1140 Canada
** F 1209-1226  Mexico

* G Geography, Maps, Anthropology, Folklore, Recreation
** GN Anthropology
** GR Folklore
** GT Manners and Customs
** GV Recreation (sports)

* H Social Sciences
** HA Statistics
** HB-HD Economics
** HE Transportation
** HF Commerce
** HG Finance
** HM Sociology
** HQ Family Life
** HV Social Pathology

* J Political Science
** JA-JC Political Theory
** JF Constitutional History 
** JK United States Politics and Government
** JX International Policies

* K Law

* L Education
** LA History of Education
** LB Teaching Methods
** LC Forms of Education

* M Music
** M Music Scores
** ML Literature of Music
** MT Music Instruction

* N Fine Arts
** NA Architecture
** NC Grapic Arts
** ND Painting
** NK Decorative Art

* P Philology and Linguistics. Languages and Literature.
** PA Classical Literature
** PC Romance Languages
** PE English Languages, Writing Guides
** PN General and Comparative Literature
** PQ Romance Literature
** PR English Literature
** PS American Literature
** PZ Juvenile Literature    
    

* Q Science

* R Medicine

* S Agriculture

* T Technology (Oddly enough, computers are in QA. ''If only there were more QA in computers ...'')

* U-V Military Science, Naval Science

* Z Bibliography and Library Science

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New letters are needed in our alphabet!

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'''Actually not. It is controlled by divisions within the divisions, a numbering system and cutter number created with infomation from the author's name. Not perfect but better than it could be. TK has most of the web stuff.'''
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Is the scheme protected by intellectual property laws (copyrights etc.)?

''No; as a project of the US government it is required to be PublicDomain''
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I simply DateStamp and then AlphabetizeEverything  --AnonymousDonor

''Categories be damned, eh?''
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CategoryOrganization