Library of Congress Classification System
| Main Classes | Subclasses |
|---|---|
| A – General Works | AE – Encyclopedias AI – Indexes AN – Newspapers AP – Periodicals |
| B – Philosophy, Psychology | B-BD – Philosophy BF – Psychology BH – Esthetics BJ – Ethics BL-BX – Religions, Mythology |
| C – History (Auxiliary sciences: archaeology, genealogy, etc.) | (various) |
| D – History (except America) | DA – Great Britain DC – France DD – Germany DK – Russia DS – Asia DT – Africa |
| E-F – America and U. S. | F1-F970 – United States F1201-F3899 – Latin America |
| G – Geography, Anthropology | G-GF – Geography, Travel, Atlases GN – Anthropology, Ethnography GR – Folklore GV – Sports |
| H – Social Sciences | HA-HJ – Economics HM-HQ – Sociology HX – Communism, Socialism, Anarchism |
| J – Political Science | |
| K – Law | |
| L – Education | |
| M – Music | ML – Literature of Music MT – Musical Instruction |
| N – Fine Arts | NA – Architecture NB – Sculpture & Related Arts NC – Graphic Arts ND – Painting NK – Applied Arts NX – The arts in general |
| P – Language and Literature | PA – Classical Philology PB-PH – Modern European Languages PJ-PL – Oriental Languages PQ – Romance Literatures PR – English Literature PS – American Literature PT – German Literature |
| Q – Science | QA – Mathematics QB – Astronomy QC – Physics QD – Chemistry QE – Geology QH – Natural History QK – Botany QL – Zoology QM – Human Anatomy QP – Physiology QR – Bacteriology |
| R – Medicine | (various) |
| S – Agriculture | (various) |
| U – Military Science | |
| V – Naval Science | |
| T – Technology & Engineering | (various) |
| Z – Bibliography & Library Science |
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A+ Research & Writing for high school and college students was created by Kathryn L. Schwartz