| A - General Works | 210 | 0.00 |
| AC - Collections. Series. | 9,549 | 0.17 |
| AE - Encyclopedias | 716 | 0.01 |
| AG - Dictionaries and other reference | 381 | 0.01 |
| AI - Indexes | 231 | 0.00 |
| AM - Museums. Collectors and collecting | 1,214 | 0.02 |
| AN - Newspapers | 83 | 0.00 |
| AP - Periodicals | 3,056 | 0.05 |
| AS - Academies and learned societies | 8,072 | 0.14 |
| AY - Yearbooks. Almanacs. Directories | 407 | 0.01 |
| AZ - History of scholarship and learning | 443 | 0.01 |
| B - Philosophy; Psychology; Religion | 33,394 | 0.59 |
| BC - Logic | 1,804 | 0.03 |
| BD - Speculative philosophy | 4,694 | 0.08 |
| BF - Psychology | 21,653 | 0.38 |
| BH - Aesthetics | 1,620 | 0.03 |
| BJ - Ethics | 5,941 | 0.11 |
| BL - Religions. Mythology. Rationalism | 23,155 | 0.41 |
| BM - Judaism | 7,170 | 0.13 |
| BP - Islam. Bahaism. Theosophy | 23,492 | 0.42 |
| BQ - Buddhism | 8,200 | 0.14 |
| BR - Christianity | 12,219 | 0.22 |
| BS - The Bible | 11,259 | 0.20 |
| BT - Doctrinal Theology | 6,389 | 0.11 |
| BV - Practical Theology | 7,870 | 0.14 |
| BX - Christian Denominations | 26,504 | 0.47 |
| C - Auxiliary Science of History | 16,595 | 0.29 |
| CB - History of Civilization | 3,956 | 0.07 |
| CC - Archaeology | 2,961 | 0.05 |
| CD - Diplomatics. Archives. Seals | 4,521 | 0.08 |
| CE - Technical Chronology. Calendar | 459 | 0.01 |
| CJ - Numismatics | 2,217 | 0.04 |
| CN - Inscriptions. Epigraphy | 764 | 0.01 |
| CR - Heraldry | 1,244 | 0.02 |
| CS - Genealogy | 4,587 | 0.08 |
| CT - Biography | 5,844 | 0.10 |
| D - History General | 41,504 | 0.73 |
| DA - History of Great Britain - History of Ireland - History of the British Isles | 23,579 | 0.42 |
| DAW - History of Central Europe | 66 | 0.00 |
| DB - History of Austria - Liechtenstein - Hungary - Czechoslovakia | 9,277 | 0.16 |
| DC - History of France - Andorra - Monaco | 22,782 | 0.40 |
| DD - History of Germany | 20,660 | 0.37 |
| DE - History of the Greco-Roman World | 1,377 | 0.02 |
| DF - History of Greece | 4,980 | 0.09 |
| DG - History of Italy - Malta | 15,757 | 0.28 |
| DH - History of Low Countries - Benelux Countries | 1,242 | 0.02 |
| DJ - History of the Netherlands | 1,165 | 0.02 |
| DJK - History of Eastern Europe | 787 | 0.01 |
| DK - History of Russia; Soviet Union; Former Soviet Republics - History of Poland | 27,546 | 0.49 |
| DL - History of Northern Europe; Scandavia | 1,883 | 0.03 |
| DP - History of Spain - Portugal | 9,040 | 0.16 |
| DQ - History of Switzerland | 986 | 0.02 |
| DR - History of the Balkan Peninsula | 13,866 | 0.25 |
| DS - History of Asia | 168,194 | 2.97 |
| DT - History of Africa | 24,047 | 0.43 |
| DU - History of Oceania (South Seas) | 4,762 | 0.08 |
| DX - History of Gypsies | 316 | 0.01 |
| E - History of America | 49,963 | 0.88 |
| F - Local History of the United States and British; French; and Latin America | 50,910 | 0.90 |
| G - Geography; Anthropology; Recreation | 10,112 | 0.18 |
| GA - Mathematical geography; Cartography | 1,441 | 0.03 |
| GB - Physical geography | 7,048 | 0.12 |
| GC - Oceanography | 1,546 | 0.03 |
| GE - Environmental Sciences | 1,293 | 0.02 |
| GF - Human ecology; Anthropogeography | 1,474 | 0.03 |
| GN - Anthropology | 12,949 | 0.23 |
| GR - Folklore | 9,001 | 0.16 |
| GT - Manners and customs (General) | 4,597 | 0.08 |
| GV - Recreation; Leisure | 10,203 | 0.18 |
| H - Social sciences (General) | 6,488 | 0.11 |
| HA - Statistics | 5,949 | 0.11 |
| HB - Economic theory; Demography | 17,297 | 0.31 |
| HC - Economic history and conditions | 49,495 | 0.88 |
| HD - Industries; Land use; Labor | 83,671 | 1.48 |
| HE - Transportation and communications | 15,673 | 0.28 |
| HF - Commerce | 23,599 | 0.42 |
| HG - Finance | 20,307 | 0.36 |
| HJ - Public Finance | 9,810 | 0.17 |
| HM - Sociology (General) | 9,433 | 0.17 |
| HN - Social history and conditions; Social problems; Social reform | 14,863 | 0.26 |
| HQ - The family; Marriage; Woman; Sexuality | 23,274 | 0.41 |
| HS - Societies: secret; benevolent; etc. | 1,379 | 0.02 |
| HT - Communities; Classes; Races | 10,840 | 0.19 |
| HV - Social pathology; Social and public welfare ; Criminology | 31,018 | 0.55 |
| HX - Socialism. Communism. Anarchism | 13,111 | 0.23 |
| J - General legislative and executive papers | 2,951 | 0.05 |
| JA - Political science (General) | 4,802 | 0.08 |
| JC - Political theory. The state. Theories of the state. | 10,971 | 0.19 |
| JF - Political institutions and public administration - General | 3,277 | 0.06 |
| JJ - Political institutions and public administration - North America | 5 | 0.00 |
| JK - Political institutions and public administration - United States | 10,252 | 0.18 |
| JL - Political institutions and public administration - Canada; Latin America; etc. | 2,656 | 0.05 |
| JN - Political institutions and public administration - Europe | 15,615 | 0.28 |
| JQ - Political Institutions and public administration - Asia; Africa; Australia; Pacific Area; etc. | 17,574 | 0.31 |
| JS - Local government. Municipal government | 7,355 | 0.13 |
| JV - Colonies and colonization. Emigration and Immigration. International migration | 3,405 | 0.06 |
| JX - International law (obsolete) | 11,826 | 0.21 |
| JZ - International relations | 1,726 | 0.03 |
| K - Law | 3,624 | 0.06 |
| KB - Religious law | 12 | 0.00 |
| KBM - Jewish Law | 9 | 0.00 |
| KBP - Islamic law | 244 | 0.00 |
| KBQ - Religious law | 1 | 0.00 |
| KBR - History of canon law | 18 | 0.00 |
| KBU - Law of the Roman Catholic Church | 15 | 0.00 |
| KDK - Law (United Kingdom and Ireland | 967 | 0.02 |
| KDZ - Law (America. North America) | 58 | 0.00 |
| KE - Law (Canada) | 360 | 0.01 |
| KF - Law (United States) | 10,492 | 0.19 |
| KG - Law (Latin America - Mexico and Central America - West Indies. Caribbean area) | 219 | 0.00 |
| KH - Law (South America) | 213 | 0.00 |
| KJ - Law (Europe) | 1,890 | 0.03 |
| KK - Law (Europe) | 1,464 | 0.03 |
| KL - Law (History of law. The ancient orient) | 470 | 0.01 |
| KM - Law (Asia) | 227 | 0.00 |
| KN - Law (South Asia. Southeast Asia. East Asia) | 3,030 | 0.05 |
| KP - Law (South Asia. Southeast Asia. East Asia) | 1,142 | 0.02 |
| KQ - Law (Africa) | 87 | 0.00 |
| KR - Law (Africa) | 157 | 0.00 |
| KS - Law (Africa) | 2,536 | 0.04 |
| KT - Law (Africa) | 134 | 0.00 |
| KU - Law (Pacific Area) | 42 | 0.00 |
| KV - Law (Pacific Area) | 59 | 0.00 |
| KW - Law (Pacific Area) | 55 | 0.00 |
| KWX - Law (Pacific Area) | 5 | 0.00 |
| KZ - Law of Nations. International law | 439 | 0.01 |
| L - Education | 2,923 | 0.05 |
| LA - History of Education | 13,103 | 0.23 |
| LB - Theory and practice of education | 32,457 | 0.57 |
| LC - Special aspects of education | 14,575 | 0.26 |
| LD - Education (Individual Institutions - United States) | 3,666 | 0.06 |
| LE - Education (Individual Institutions - America (except United States)) | 363 | 0.01 |
| LF - Education (Individual Institutions - Europe) | 2,384 | 0.04 |
| LG - Education (Individual Institutions - Asia; Africa; Indian Ocean Islands; Australia; New Zealand; Pacific Islands) | 1,346 | 0.02 |
| LH - College and school magazines and papers | 198 | 0.00 |
| LJ - Student fraternities; United States | 251 | 0.00 |
| LT - Textbooks | 141 | 0.00 |
| M - Printed Music | 50,722 | 0.90 |
| ML - Literature on music | 29,635 | 0.52 |
| MT - Musical instruction and study | 5,512 | 0.10 |
| N - Visual arts | 35,921 | 0.64 |
| NA - Architecture | 25,059 | 0.44 |
| NB - Sculpture | 6,705 | 0.12 |
| NC - Drawing. Design. Illustration | 5,766 | 0.10 |
| ND - Painting | 25,184 | 0.45 |
| NE - Print media | 3,608 | 0.06 |
| NK - Decorative arts | 12,745 | 0.23 |
| NX - Arts in general | 3,273 | 0.06 |
| P - Language and Literature | 12,392 | 0.22 |
| PA - Greek and Latin language and literature | 7,712 | 0.14 |
| PB - Modern languages; Celtic languages | 823 | 0.01 |
| PC - Romanic languages | 2,651 | 0.05 |
| PE - English language | 2,465 | 0.04 |
| PF - West Germanic languages | 648 | 0.01 |
| PG - Slavic languages; Baltic languages; Albanian language | 16,914 | 0.30 |
| PH - Uralic languages; Basque language | 2,837 | 0.05 |
| PJ - Oriental philology and literature | 48,723 | 0.86 |
| PK - Indo-Iranian philology and literature | 62,548 | 1.11 |
| PL - Languages of Eastern Asia; Africa; Oceania | 102,474 | 1.81 |
| PM - Hyperborean; Indian; and artificial languages | 1,316 | 0.02 |
| PN - Literature (General) | 37,419 | 0.66 |
| PQ - French literature - Italian literature - Spanish literature - Portuguese literature | 20,784 | 0.37 |
| PR - English literature | 27,484 | 0.49 |
| PS - American literature | 20,715 | 0.37 |
| PT - German; Dutch; Scandinavian; Old Norse; Old Icelandic; Old Norwegian; Modern Icelandic; Faroese; Danish; Norwegian; and Swedish literature; Flemish literature since 1830 | 7,433 | 0.13 |
| PZ - Fiction and juvenile belles lettres | 6,247 | 0.11 |
| Q - Science (General) | 11,757 | 0.21 |
| QA - Mathematics | 47,134 | 0.83 |
| QB - Astronomy | 8,864 | 0.16 |
| QC - Physics | 24,313 | 0.43 |
| QD - Chemistry | 14,384 | 0.25 |
| QE - Geology | 12,603 | 0.22 |
| QH - Natural history - Biology | 15,873 | 0.28 |
| QK - Botany | 12,957 | 0.23 |
| QL - Zoology | 14,298 | 0.25 |
| QM - Human anatomy | 2,358 | 0.04 |
| QP - Physiology | 12,645 | 0.22 |
| QR - Microbiology | 3,699 | 0.07 |
| R - Medicine (General) | 9,654 | 0.17 |
| RA - Public aspects of medicine | 14,714 | 0.26 |
| RB - Pathology | 2,752 | 0.05 |
| RC - Internal medicine | 34,993 | 0.62 |
| RD - Surgery | 8,207 | 0.15 |
| RE - Ophthalmology | 1,918 | 0.03 |
| RF - Otorhinolaryngology | 1,010 | 0.02 |
| RG - Gynecology and obstetrics | 3,533 | 0.06 |
| RJ - Pediatrics | 5,470 | 0.10 |
| RK - Dentistry | 9,451 | 0.17 |
| RL - Dermatology | 690 | 0.01 |
| RM - Therapeutics. Pharmacology | 5,116 | 0.09 |
| RS - Pharmacy and materia medica | 2,871 | 0.05 |
| RT - Nursing | 5,141 | 0.09 |
| RV - Botanic; Thomsonian; and eclectic medicine | 12 | 0.00 |
| RX - Homeopathy | 55 | 0.00 |
| RZ - Other systems of medicine | 172 | 0.00 |
| S - Agriculture (General) | 7,607 | 0.13 |
| SB - Plant culture | 7,227 | 0.13 |
| SD - Forestry | 10,073 | 0.18 |
| SF - Animal culture | 2,346 | 0.04 |
| SH - Aquaculture. Fisheries. Angling. | 2,496 | 0.04 |
| SK - Hunting sports | 878 | 0.02 |
| T - Technology (General) | 7,766 | 0.14 |
| TA - Engineering (General). Civil Engineering | 15,342 | 0.27 |
| TC - Hydraulic engineering - Ocean Engineering | 3,654 | 0.06 |
| TD - Environmental technology. Sanitary engineering | 8,471 | 0.15 |
| TE - Highway engineering. Roads and pavements | 1,838 | 0.03 |
| TF - Railroad engineering and operation | 2,103 | 0.04 |
| TG - Bridge engineering | 1,133 | 0.02 |
| TH - Building construction | 3,715 | 0.07 |
| TJ - Mechanical engineering and machinery | 8,909 | 0.16 |
| TK - Electrical engineering. Electronics. Nuclear engineering | 18,611 | 0.33 |
| TL - Motor vehicles. Aeronautics. Astronautics | 9,139 | 0.16 |
| TN - Mining engineering. Metallurgy | 6,272 | 0.11 |
| TP - Chemical technology | 7,686 | 0.14 |
| TR - Photography | 6,913 | 0.12 |
| TS - Manufactures | 6,026 | 0.11 |
| TT - Handicrafts. Arts and crafts | 1,467 | 0.03 |
| TX - Home economics | 3,390 | 0.06 |
| U - Military Science (General) | 4,680 | 0.08 |
| UA - Armies: Organization; distribution; military situation | 6,840 | 0.12 |
| UB - Military administration | 2,220 | 0.04 |
| UC - Maintenance and transportation | 538 | 0.01 |
| UD - Infantry | 169 | 0.00 |
| UE - Cavalry. Armor | 99 | 0.00 |
| UF - Artillery | 747 | 0.01 |
| UG - Military engineering | 2,166 | 0.04 |
| UH - Other services | 316 | 0.01 |
| V - Naval science (General) | 1,025 | 0.02 |
| VA - Navies: Organization; distribution; naval situation | 810 | 0.01 |
| VB - Naval administration | 156 | 0.00 |
| VC - Naval maintenance | 65 | 0.00 |
| VD - Naval seaman | 4 | 0.00 |
| VE - Marines | 125 | 0.00 |
| VF - Naval ordnance | 49 | 0.00 |
| VG - Minor services of navies | 179 | 0.00 |
| VK - Navigation. Merchant marine | 1,378 | 0.02 |
| VM - Naval architecture. Shipbuilding. Marine engineering | 2,400 | 0.04 |
| Z - Books (General). Writing. Paleography. Book industries and trade. Libraries. Bibliography | 76,028 | 1.34 |
| ZA - Information Resources | 222 | 0.00 |
