A = GENERAL WORKS General Encyclopedias, Reference books B = PHILOSOPHY - RELIGION B-BJ Philosophy BF Psychology BL-BX Religion C = AUXILIARY SCIENCES OF HISTORY CB History of civilization CC Archaeology CD Archives CJ Numismatics CR Heraldry CS Genealogy CT Biography (general) D = HISTORY: GENERAL, OLD WORLD D World History DA Great Britain DB Austria DC France DD Etc., (other individual countries) E-F = HISTORY OF AMERICA E1-143 America E151-857 United States F1-957 United States: state and local F1201 Etc., (other individual countries) G = GEOGRAPHY, ANTHROPOLOGY, SPORTS G Geography GB Physical Geography GN Anthropology GR Folklore GV Recreation H = SOCIAL SCIENCES HA Statistics HB-HJ Economics HM-HX Sociology J = POLITICAL SCIENCE JA-JC Political Science JF-JQ Constitutional History and Public Administration JS Local Government K = LAW L = EDUCATION LB Theory and Practice LD-LG Schools and Colleges

M = MUSIC M Scores ML Literature of Music MT Musical Instruction N = FINE ARTS NA Architecture ND Painting P = LANGUAGE, LITERATURE P Philology and Linguistics PA Classical Languages and Lit. PC Romance Languages PD-PF Germanic Languages PG Slavic Languages and Lit. PJ-PL Oriental Languages and Lit. PN General and Comparative Lit. PQ Romance Literatures PR English Literature PS American Literature PT Germanic 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 R = MEDICINE RA Public Aspects Medicine RC Internal Medicine RM Theraputics, Pharmacy RT Nursing S = AGRICULTURE T = TECHNOLOGY TA Engineering, Civil Engineering TD Environmental Engineering TK Electrical Engineering TN Mining, Metallurgy TP Chemical Engineering TR Photography U = MILITARY SCIENCE V = NAVAL SCIENCE Z = BIBLIOGRAPHY, LIBRARY SCIENCE