Library of Congress Classification (LCC)
The Library of Congress Classification (LCC) is the primary classification system used by the Library of Congress and most large academic and research libraries in the United States and globally. Developed starting in the late 19th century (first outline in 1904) and continuously updated, it organizes knowledge into 21 major classes (A–Z, excluding I, O, W, X, and Y for historical reasons). Each class is divided into subclasses (alphanumeric codes like QA for Mathematics), with further hierarchical breakdowns using numbers (1–9999) and decimals for specificity. Unlike the Dewey Decimal system, LCC is enumerative (lists topics explicitly) and shows hierarchy through indentation rather than continuous numerical subdivision.
LCC is practical, tailored to the Library of Congress’s vast collection (over 175 million items as of 2025), and emphasizes English-language and Western scholarship, though it covers global topics. Updates are issued regularly via the Classification and Shelflisting Manual and supplements; as of November 2025, recent additions include expansions for artificial intelligence (under QA76), climate change and sustainability (under QC and HD), quantum computing (QA76), digital humanities (under AZ and P), and biomedical ethics/AI in medicine (under R). The full schedules are available in 44 PDF volumes (data current to August 2025), with online access via Classification Web Plus.
Below is the full hierarchical outline of major classes, subclasses, and key subcategories, based on the official LCC Outline (updated May 2024, with 2025 supplements noted). This is a condensed version for clarity—full details span thousands of pages.
How the Library of Congress Organizes Knowledge
A – GENERAL WORKS
- Encyclopedias, periodicals, newspapers, societies, associations
- Collected works (by form, e.g., polygraphies)
- Subclasses: AC Collections; AE Encyclopedias; AI–AN Periodicals; AP Periodicals (misc.); AQ Societies; AY Yearbooks, almanacs
- 2025 Update: Expansion for open-access digital repositories (AC120–AC185)
B – PHILOSOPHY. PSYCHOLOGY. RELIGION
- B Philosophy (general): Ontology, epistemology, logic, metaphysics
- BC Logic
- BD Speculative philosophy
- BF Psychology (general, parapsychology, consciousness studies)
- BH Aesthetics
- BJ Ethics, social usages
- BL–BR Religion (general, comparative, world religions: BL–BL999 non-Christian; BM Judaism; BP Islam, Bahai; BQ Buddhism; BR Christianity; BS Bible; BT Doctrinal theology; BV Practical theology; BX Christian denominations)
- 2025 Update: New subclass for philosophy of AI and transhumanism (BD450–BD465); expansions in BF for neuroethics and cognitive AI (BF76.4–BF76.7)
C – AUXILIARY SCIENCES OF HISTORY
- C General auxiliary sciences
- CB History of civilization
- CC Archaeology
- CD Diplomatics, archives
- CE Chronology
- CI Genealogy (now in CS)
- CJ Numismatics
- CN Inscriptions
- CR Heraldry
- CS Genealogy
- CT Biography (general)
- 2025 Update: Digital archaeology and GIS in archaeology (CC120–CC135)
D–F – HISTORY: GENERAL AND OLD WORLD / NEW WORLD
- D History (general): World history, historiography, by period (DA–DE.1 Great Britain/Ireland; DF Greece; DG Italy/Rome; DH Low Countries; DJ Netherlands; DJK Eastern Europe; DK Russia; DL Northern Europe; DP Spain/Portugal; DQ France; DR Balkans; DS Asia; DT Africa; DU Oceania)
- E History: United States (E11–E99 Native Americans; E176–E377 General U.S.; E457–E499 Abraham Lincoln era; F1–F975 Regional U.S./Canada)
- F History: Western Hemisphere (Latin America, Mexico, Caribbean; e.g., F1201–F3799 Mexico/Central America)
- 2025 Update: Subclasses for digital history and global decolonization studies (D16.14–D16.145; DA125–DA129 for UK digital archives)
G – GEOGRAPHY. ANTHROPOLOGY. RECREATION
- G Geography (general), mathematical geography, cartography, map projections
- GA Mathematical geography, geodesy
- GC Oceanography
- GE Environmental sciences (human ecology, sustainability)
- GF Anthropogeography
- GN Anthropology (physical, cultural, ethnology)
- GR Folklore
- GT Manners and customs
- GV Recreation, leisure (sports, games, dance)
- 2025 Update: Climate change modeling and geospatial AI (GE149–GE170; G70.63–G70.69 for GIS in climate science)
H – SOCIAL SCIENCES
- H Social sciences (general)
- HA Statistics
- HB Economic theory, demography
- HC Economic history/conditions
- HD Economic history (industries, land, agriculture, labor)
- HE Transportation/aeronautics
- HF Commerce (business, accounting, finance, marketing)
- HG Finance (banking, money, securities)
- HJ Public finance
- HM Sociology (general, theory)
- HN Social history/problems
- HQ Family, marriage, women, sexual life
- HS Societies (secret, benevolent)
- HT Communities, classes, races
- HV Social pathology (criminology, protection of animals)
- HX Socialism, communism, anarchism
- 2025 Update: Digital economy and crypto-economics (HF5548.32–HF5548.37); social impacts of AI (HM851–HM871)
J – POLITICAL SCIENCE
- J Political science (general)
- JA Political science (general, theory)
- JC Political theory (ancient to modern)
- JF Political institutions/processes
- JJ Political institutions (U.S.)
- JK Political institutions (North America)
- JL Political institutions (Central/South America)
- JN Political institutions (Europe)
- JQ Political institutions (Asia, Africa, Australia)
- JS Local government
- JZ International relations
- 2025 Update: Cyber diplomacy and space law (JZ6368–JZ6370)
K – LAW
- K Law (general): Comparative/international law
- K1–K90 Law in general (comparative)
- KA–KZ Subarranged by region (e.g., KD England; KE Canada; KF U.S.)
- K International law (public, private)
- 2025 Update: AI regulation and data privacy law (K564.C58–K564.C62); environmental law expansions (K3581–K3590 for climate litigation)
L – EDUCATION
- L Education (general)
- LA History of education
- LB Theory/practice of education (school management, higher ed)
- LC Special education (comparative, special topics like edtech)
- LD U.S. higher education (individual institutions)
- LE American/English schools
- LF Europe
- LG Asia/Africa/Oceania
- LH College publications
- LJ Student societies
- LT Textbooks
- 2025 Update: AI in education and lifelong digital learning (LB1028.43–LB1028.48)
M – MUSIC AND BOOKS ON MUSIC
- M Musical scores (by instrument/voice: M1–M5 Collected works; M6–M175 Keyboard; M176–M199 Solo voices; M200–M386 Vocal/choral; M400–M5000 Orchestral/ensemble)
- ML Literature on music (ML1–ML423 General history/criticism; ML430–ML458 Composers; ML460–ML538 Notation; ML540–ML554 Instruments; ML555–ML729 Vocal music; ML730–ML755 World music; ML1566–ML3775 Discography)
- MT Musical instruction/study (MT1–MT5 Dictionaries; MT6–MT67 Systems; MT130–MT136 Voice; MT140–MT180 Keyboard; MT196–MT258 String instruments; MT259–MT336 Wind instruments; MT342–MT383 Percussion; MT442–MT452 Ensemble; MT556–MT649 Composition; MT882–MT915 Program music)
- 2025 Update: Digital musicology and AI composition (ML3837–ML3840; MT191–MT192 for algorithmic music)
N – FINE ARTS
- N Visual arts (general): History of art, aesthetics
- NA Architecture (NA100–NA890 History; NA900–NA924 Special types; NA4100–NA8480 By country/period)
- NB Sculpture
- NC Drawing, design, illustration
- ND Painting
- NE Print media
- NK Decorative arts/applied arts
- NX Arts in general (theory, philosophy)
- 2025 Update: Digital and generative art, NFTs (N72.D56–N72.D6; NC177–NC182 for AI-generated illustration)
P – LANGUAGE AND LITERATURE
- P Philology, linguistics (general)
- PA Classical languages/literature (Greek, Latin)
- PB Modern European languages
- PC Romanic languages (French, Italian, Spanish)
- PD Germanic languages (English, German)
- PE English language
- PF West Germanic/Scandinavian
- PG Slavic languages/literature
- PH Finno-Ugric/Basque
- PJ–PK Oriental philology/literature (PJ Semitic; PK Indo-Iranian; PL East/Southeast Asian; PM Indigenous American)
- PN General literature (PN1–PN6790 Literary history/criticism; PN441–PN1009 Drama; PN1990–PN1992.92 Film/radio/TV; PN1995–PN1999 Broadcasting; PN2000–PN3461 Performing arts; PN4000–PN4350 Oratory; PN6000–PN6790 By region/period)
- PO Portuguese literature (now in PQ)
- PQ French, Italian, Spanish/Portuguese literature
- PR English literature
- PS American literature
- PT Germanic literature
- PZ Fiction/juvenile literature
- 2025 Update: Computational linguistics and NLP (P98.C65–P98.C66); digital humanities (P98.D56–P98.D6)
Q – SCIENCE
- Q Science (general): General science, learned societies, history of science
- QA Mathematics (QA1–QA939 Pure/applied: QA1–QA43 General; QA47–QA59 Tables; QA71–QA90 Instruments; QA101–QA145 Arithmetic; QA150–QA272 Algebra; QA273–QA280 Probabilities; QA299–QA300 Analysis; QA440–QA699 Geometry; QA800–QA939 Numerical analysis)
- QB Astronomy
- QC Physics (QC1–QC999: QC21–QC75 Classical; QC100–QC179 Electromagnetism; QC176–QC197 Optics; QC350–QC390 Thermodynamics; QC670–QC739 Nuclear; QC770–QC849 High energy; QC901–QC999 Geophysics)
- QD Chemistry
- QE Geology
- QH Natural history – Biology (QH1–QH278 General; QH301–QH705 General biology; QH426–QH470 Genetics; QH471–QH489 Reproduction; QH540–QH671 Ecology)
- QK Botany
- QL Zoology
- QM Human anatomy
- QP Physiology
- QR Microbiology
- 2025 Update: AI/ML in science (QA76.9.M35–QA76.9.M38); quantum information science (QA76.889–QA76.89); climate modeling (QC981.8.C5–QC981.8.C54)
R – MEDICINE
- R Medicine (general): General practice, history, dictionaries
- RA Public health (RA1–RA1270 General; RA395–RA418.5 Health care economics; RA421–RA790 Public health; RA1001–RA1175 Hygiene; RA1190–RA1270 Disaster/emergency medicine)
- RB Pathology
- RC Internal medicine (RC31–RC1245 General; RC155–RC275 Infectious; RC321–RC571 Neurosciences; RC581–RC951 Immunology; RC952–RC1245 Geriatrics/specialties)
- RD Surgery
- RE Ophthalmology
- RF Otorhinolaryngology
- RG Gynecology/obstetrics
- RJ Pediatrics
- RK Dentistry
- RL Dermatology
- RM Therapeutics/pharmacology
- RS Pharmacy/materia medica
- RT Nursing
- RX Homeopathy
- RZ Other systems (alternative medicine)
- 2025 Update: Telemedicine and AI diagnostics (RA975.5.T35–RA975.5.T36; RC552.A24–RC552.A245 for AI in mental health)
S – AGRICULTURE
- S Agriculture (general)
- SB Plant culture (SB1–SB960 General; SB317–SB406 Field/industrial crops; SB401–SB476 Ornamental plants; SB601–SB700 Landscape architecture; SB711–SB960 Pests/diseases)
- SD Forestry
- SF Animal culture (veterinary medicine)
- SH Aquaculture/fisheries
- SK Game/hunting
- 2025 Update: Sustainable agriculture and precision farming (S494.5.B54–S494.5.B545 for biotech/AI in ag)
T – TECHNOLOGY
- T Technology (general): General engineering, history, patents
- TA General civil engineering
- TC Hydraulic engineering
- TD Sanitary/municipal engineering (environmental engineering)
- TE Highway engineering
- TF Railroad engineering
- TG Bridge engineering
- TH Building construction
- TJ Mechanical engineering/machines
- TK Electrical engineering (TK1–TK9971: TK7800–TK8360 Electronics; TK7867–TK7869 Computer hardware)
- TL Motor vehicles/aeronautics
- TN Mining engineering
- TP Chemical technology
- TR Photography
- TS Manufactures
- TT Handicrafts
- TX Home economics
- 2025 Update: Renewable energy tech (TK2896–TK2990 for solar/wind); robotics/AI engineering (TJ210.2–TJ211.4)
U – MILITARY SCIENCE
- U Military science (general): General works, war (theory, causes)
- UA Armies (organization, equipment)
- UB Military administration
- UC Military maintenance/supply
- UD Infantry
- UE Cavalry
- UF Artillery
- UG Military engineering
- UH Other military branches
- 2025 Update: Cyber warfare (UA25–UA30)
V – NAVAL SCIENCE
- V Naval science (general)
- VA Navies (organization, distribution)
- VB Naval administration
- VC Naval maintenance
- VD Naval seaman-ship
- VE Marines
- VF Naval ordnance
- VG Minor components
- VM Shipbuilding/naval construction
- VN Naval art/science
- 2025 Update: Autonomous naval systems (V773–V775)
Z – BIBLIOGRAPHY. LIBRARY SCIENCE. INFORMATION RESOURCES (GENERAL)
- Z Books (general), writing, paleography, book industries, libraries, bibliography
- ZA Information resources (general, data processing, digital libraries)
- Z4–Z100 General bibliography
- Z101–Z899 National bibliography
- Z1201–Z4980 Subject bibliography
- Z5001–Z7999 Book history/manufacture
- Z1001–Z1005 Writing
- Z116–Z120 Paleography
- Z200–Z260 Book industries/trade
- Z270–Z360 Bookbinding
- Z665–Z1000.8 Library science (general, operations, administration)
- Z1019–Z1045 Libraries (by country)
- Z1201–Z4980 Subject bibliography (e.g., Z5051–Z5076 Agriculture)
- 2025 Update: Digital libraries and information science (ZA4060–ZA4480 for AI in info retrieval; Z699.5.D38 for blockchain in libraries)
Sarvarthapedia Cross-Referenced Conceptual Network (LCC-Aligned Knowledge Web)
Core Meta-Structure
Knowledge Organization System (KOS)
- Anchors: Classification, ontology, taxonomy, epistemology
- LCC Root: A (General Works), Z (Bibliography & Information Science)
- Cross-links:
- Information Retrieval → Z, ZA
- Digital Libraries → ZA4060–ZA4480
- Knowledge Graphs → QA (Mathematics), HM (Sociology of knowledge), ZA
Epistemic Foundations
- Anchors: Epistemology, logic, philosophy of knowledge
- LCC Root: B (Philosophy), BC (Logic), BD (Metaphysics)
- Cross-links:
- Scientific Method → Q (Science)
- Historiography → D (History)
- AI Epistemology → BD450–BD465
Cluster: Knowledge Production & Representation
Scholarly Communication
- Anchors: Publishing, peer review, open access
- LCC Root: Z (Book industries, libraries), A (General works)
- Cross-links:
- Digital Repositories → AC120–AC185
- Bibliometrics → Z665–Z1000.8, HA (Statistics)
- Academic Writing → PE (Language), PN (Literature)
Language & Meaning Systems
- Anchors: Linguistics, semiotics, textual interpretation
- LCC Root: P (Language & Literature)
- Cross-links:
- Computational Linguistics → P98.C65–P98.C66
- Digital Humanities → P98.D56–P98.D6, AZ
- Philosophy of Language → B
Cluster: Scientific Knowledge Systems
Formal Sciences
- Anchors: Mathematics, logic, computation
- LCC Root: QA (Mathematics)
- Cross-links:
- Artificial Intelligence → QA76, QA76.9.M35–M38
- Quantum Computing → QA76.889–QA76.89
- Statistics → HA
Natural Sciences
- Anchors: Physics, chemistry, biology, earth systems
- LCC Root: Q (Science: QC, QD, QH, QE)
- Cross-links:
- Climate Science → QC981.8.C5–C54, GE
- Ecology → QH540–QH671
- Biotechnology → TP, S
Applied Sciences & Technology
- Anchors: Engineering, systems design, innovation
- LCC Root: T (Technology)
- Cross-links:
- Robotics → TJ210.2–TJ211.4
- Renewable Energy → TK2896–TK2990
- Information Technology → TK7867–TK7869
Cluster: Human Systems & Society
Social Structures
- Anchors: Sociology, economics, demographics
- LCC Root: H (Social Sciences)
- Cross-links:
- Digital Economy → HF5548.32–HF5548.37
- Social Impacts of AI → HM851–HM871
- Urban Systems → HT
Governance & Power
- Anchors: Political systems, law, institutions
- LCC Root: J (Political Science), K (Law)
- Cross-links:
- International Relations → JZ
- AI Regulation → K564.C58–K564.C62
- Cyber Diplomacy → JZ6368–JZ6370
Culture & Identity
- Anchors: Anthropology, folklore, customs
- LCC Root: G (Anthropology), GR, GT
- Cross-links:
- Cultural Narratives → PN (Literature)
- Heritage Studies → C (Auxiliary sciences of history)
- Digital Culture → NX, N72.D56
Cluster: Historical Knowledge
Temporal Knowledge Systems
- Anchors: Chronology, historiography
- LCC Root: C (Chronology), D (History)
- Cross-links:
- Digital History → D16.14–D16.145
- Archaeological Data Systems → CC120–CC135
- Biography → CT
Regional & Global Histories
- Anchors: Civilizations, regions, comparative history
- LCC Root: D–F
- Cross-links:
- Postcolonial Studies → DS, DT, F
- Globalization → H, JZ
- Cultural Exchange → P, N
Cluster: Cognitive & Biological Systems
Mind & Cognition
- Anchors: Psychology, consciousness, cognition
- LCC Root: BF (Psychology)
- Cross-links:
- Cognitive Science → BF, QP
- Neuroethics → BF76.4–BF76.7, R
- AI Cognition → QA76, BD
Health & Medicine
- Anchors: Public health, clinical systems
- LCC Root: R (Medicine)
- Cross-links:
- AI in Medicine → RA975.5.T35–T36
- Mental Health → RC
- Bioethics → BJ, R
Cluster: Environmental & Planetary Systems
Earth Systems & Sustainability
- Anchors: Ecology, climate, sustainability
- LCC Root: GE (Environmental Sciences), QC (Climate Physics)
- Cross-links:
- Climate Modeling → QC981.8.C5–C54
- Sustainable Development → HD, S
- Geospatial AI → G70.63–G70.69
Agriculture & Resource Systems
- Anchors: Food systems, land use
- LCC Root: S (Agriculture)
- Cross-links:
- Precision Farming → S494.5.B54–B545
- Food Security → HD, RA
- Biotechnology → TP
Cluster: Creative & Expressive Systems
Arts & Aesthetics
- Anchors: Visual arts, performance, aesthetics
- LCC Root: N (Fine Arts), BH (Aesthetics)
- Cross-links:
- Digital Art → N72.D56–N72.D6
- Architecture → NA
- Cultural Theory → HM
Music & Sonic Systems
- Anchors: Composition, performance, theory
- LCC Root: M, ML, MT
- Cross-links:
- Algorithmic Composition → MT191–MT192
- Musicology → ML
- Cognitive Music → BF
Cluster: Education & Knowledge Transmission
Learning Systems
- Anchors: Pedagogy, curriculum, institutions
- LCC Root: L (Education)
- Cross-links:
- AI in Education → LB1028.43–LB1028.48
- Knowledge Transfer → Z, HM
- Lifelong Learning → LC
Cross-Cluster Integrative Nodes
Artificial Intelligence (Universal Connector)
- LCC Anchors: QA76, TJ, HM, K, R
- Links:
- Epistemology (B)
- Social Impact (H)
- Law & Ethics (K, BJ)
- Medicine (R)
- Education (L)
Climate Change (Systemic Connector)
- LCC Anchors: QC, GE, HD
- Links:
- Policy (J, K)
- Economics (H)
- Technology (T)
- Agriculture (S)
Digital Transformation (Meta Connector)
- LCC Anchors: ZA, QA, P, N
- Links:
- Humanities (P, N)
- Science (Q)
- Society (H)
- Governance (J)
Structural Logic of the Network
Horizontal Connectivity
- Interdisciplinary bridges across clusters
- Example: AI ↔ Medicine ↔ Ethics ↔ Law
Vertical Hierarchy
- LCC Class → Subclass → Topic → Concept
- Example: Q → QA → QA76 → AI → Machine Learning
Recursive Linking
- Concepts link back to foundational domains
- Example:
- AI → Logic (BC) → Mathematics (QA) → Philosophy (B)
Sarvarthapedia network transforms LCC from a static classification into a dynamic, cross-referenced knowledge web, where each node is both a category and a conceptual gateway, enabling multidirectional exploration across disciplines.
