A   General Works
        
AC      Collections
        AE      Encyclopedias
        AG      Dictionaries    
        AI      Indexes
        AM      Museums
        AN      Newspapers
        AP      Periodicals
        AS      Academies and societies
        AY      Yearbooks.  Almanacs.  Directories
        AZ      History of scholarship


B   Philosophy.  Psychology.  Religion

        B       Philosophy (General)
        BC      Logic
        BD      Speculative philosophy
        BF      Psychology. Parapsychology.  Occultism
        BH      Aesthetics
        BJ      Ethics.  Social usages.  Etiquette
        BL      Religions.  Mythology
        BM      Judaism
        BP      Islam.  Bahaism.  Theosophy.  etc.
        BQ      Buddhism
        BR      Christianity
        BS      Bible
        BT      Christianity:  Doctrinal theology
        BV      Christianity:  Practical theology
        BX      Christian denominations
        

C   Auxiliary Sciences of History

        C       General
        CB      History of civilization
        CC      Archaeology
        CD      Diplomatics.  Archives.  Seals
        CE      Technical chronology.  Calendar
        CJ      Numismatics
        CN      Inscriptions.  Epigraphy
        CR      Heraldry
        CS      Genealogy
        CT      Biography


D   History:  General and Old World

        D       General
        DA      Great Britain
        DB      Austria.  Hungary.  Czechoslovakia
        DC      France
        DD      Germany
        DE      Mediterranean region - Classical
        DF      Greece
        DG      Italy
        DH      Low Countries:  Belgium.  Luxembourg
        DJ      Netherlands (Holland)
        DJK     Eastern Europe
        DK      Soviet Union.  Poland
        DL      Northern Europe.  Scandinavia
        DP      Spain.  Portugal
        DQ      Switzerland
        DR      Balkan Peninsula.  Turkey
        DS      Asia
        DT      Africa
        DU      Oceania.  Australia.  New Zealand
        DX      Gypsies


E - F       History:  Western Hemisphere

        E       America
        F       U.S. local history.  Canada.  Latin America


G   Geography.  Anthropology.  Recreation

        G       General.  Atlases.  Maps
        GA      Mathematical geography.  Cartography
        GB      Physical geography
        GC      Oceanography
        GF      Human ecology.  Anthropogeography
        GN      Anthropology
        GR      Folklore
        GT      Manners and customs
        GV      Recreation.  Sports.  Games


H   Social Sciences

        H       General
        HA      Statistics
        HB      Economics
        HC      Economic history
        HD      Land.  Agriculture.  Industry.  Labor
        HE      Transportation and communications
        HF      Commerce
        HG      Finance
        HJ      Public finance
        HM      Sociology
        HN      Social history
        HQ      Family.  Marriage.  Women
        HS      Societies.  Clubs
        HT      Communities.  Classes.  Races
        HV      Social pathology.  Social service.  Criminology
        HX      Socialism.  Communism



J   Political Science

        J       General legislative and executive papers
        JA      Political science - General
        JC      Political theory. The state
        JF      Constitutional history - General
        JK      Constitutional history - United States
        JL      Constitutional history - Canada.  Latin America
        JN      Constitutional history - Europe
        JQ      Constitutional history - Asia. Africa. Australia. Oceania
        JS      Local government
        JV      Colonies and colonization
        JX      International law.  International relations


K   Law

        K        General
        KD       United Kingdom and Ireland
        KDZ      America.  North America.  OAS
        KE       Canada
        KF       United States
        KG-KH   Latin America
        KJ-KK    Europe



L   Education

        L       General
        LA      History of education
        LB      Theory and practice of education
        LC      Special aspects of education
        LD      Individual institutions - U.S.
        LE      Individual institutions - Other Americas
        LF      Individual institutions - Europe
        LG      Individual institutions - Asia.  Africa.  Oceania
        LH      College publications
        LJ      Student fraternities and sororities
        LT      Textbooks


M   Music

        M       General
        ML      Literature of music
        MT      Music instruction



N   Fine Arts
        
        N       Visual arts (General)
        NA      Architecture
        NB      Sculpture
        NC      Drawing.  Design
        ND      Painting
        NE      Print media
        NK      Decorative arts.  Applied arts
        NX      Arts in general



P   Language and Literature

        P       Philology and linguistics
        PA      Classical languages and literature
        PB      Celtic languages
        PC      Romance languages
        PD      Germanic languages.  Scandinavian languages
        PE      English language
        PF      West Germanic languages.  Dutch.  German
        PG      Slavic.  Baltic.  Armenian languages and literature
        PH      Finno-Ugrian languages and literature
        PJ      Oriental languages and literature
        PK      Indo-Iranian languages and literature
        PL      East Asian languages and literatures
        PM      American Indian languages.  Artificial languages
        PN      Literature.  General literary history and collections.
                Performing arts
        PQ      Romance literatures
        PR      English literature
        PS      American literature
        PT      Germanic literatures
        PZ      Juvenile belle lettres

        
Q   Science

        Q       General
        QA      Mathematics
        QB      Astronomy
        QC      Physics
        QD      Chemistry
        QE      Geology
        QH      Natural history.  Biology
        QK      Botany
        QL      Zoology
        QM      Human anatomy
        QP      Physiology
        QR      Microbiology


R   Medicine

        R       General
        RA      Public aspects of medicine
        RB      Pathology
        RC      Internal Medicine
        RD      Surgery
        RE      Opthalmology
        RF      Otorhinolaryngology
        RG      Gynecology and obstetrics
        RJ      Pediatrics
        RK      Dentistry
        RL      Dermatology
        RM      Therapeutics.  Pharmacology
        RS      Pharmacy.  Materia medica
        RT      Nursing
        RV      Botanic.  Thomsonian.  eclectic medicine
        RX      Homeopathy
        RZ      Other systems of medicine


S   Agriculture
                
        S       General
        SB      Plant culture
        SD      Forestry
        SF      Animal culture
        SH      Aquaculture.  Fisheries.  Angling
        SK      Hunting

        
T   Technology

        T       General
        TA      Engineering - General and civil
        TC      Hydraulic engineering
        TD      Environmental technology.  Sanitary engineering
        TE      Highway engineering
        TF      Railroad engineering
        TG      Bridge construction
        TH      Building construction
        TJ      Mechanical engineering and machinery
        TK      Electrical engineering.  Electronics. Nuclear engineering
        TL      Motor vehicles.  Aeronautics.  Astronautics
        TN      Mining engineering.  Metallurgy
        TP      Chemical technology
        TR      Photography
        TS      Manufactures
        TT      Handicrafts.  Arts and crafts
        TX      Home economics


U   Military Science

        U       General
        UA      Armies
        UB      Military administration
        UC      Maintenance and transportation
        UD      Infantry
        UE      Cavalry.  Armored cavalry
        UF      Artillery
        UG      Military engineering.  Air forces.  Air warfare
        UH      Other services


V   Naval Science

        
        V       General
        VA      Navies
        VB      Naval administration
        VC      Naval maintenance
        VD      Naval seamen
        VE      Marines
        VF      Naval ordnance
        VG      Minor services of navies
        VK      Navigation.  Merchant marine
        VM      Naval architecture.  Marine engineering


Z   Bibliography:  Library Science

        Z       Books. Book industries. Libraries. Library science. 
                Bibliography