LIBRARY OF CONGRESS CLASSIFICATION OUTLINE 

CLASS Q - SCIENCE

(Click each subclass for details) 

Subclass Q Science (General)

Subclass QA Mathematics

Subclass QB Astronomy

Subclass QC Physics

Subclass QD Chemistry

Subclass QE Geology

Subclass QH Natural history - Biology 

Subclass QK Botany

Subclass QL Zoology

Subclass QM Human anatomy

Subclass QP Physiology

Subclass QR Microbiology
Subclass Q 

Q1-390 Science (General)

Q1-295 General

Q300-390 Cybernetics

Q350-390 Information theory
Subclass QA 

QA1-939 Mathematics

QA1-43 General

QA47-59 Tables

QA71-90 Instruments and machines

QA75-76.95 Calculating machines

QA75.5-76.95 Electronic computers. Computer science

QA76.75-76.765 Computer software

QA101-(145) Elementary mathematics. Arithmetic

QA150-272.5 Algebra

QA273-280 Probabilities. Mathematical statistics

QA299.6-433 Analysis

QA440-699 Geometry. Trigonometry. Topology

QA801-939 Analytic mechanics
Subclass QB 

QB1-991 Astronomy

QB1-139 General

QB140-237 Practical and spherical astronomy

QB275-343 Geodesy

QB349-421 Theoretical astronomy and celestial mechanics

QB455-456 Astrogeology

QB460-466 Astrophysics

QB468-480 Non-optical methods of astronomy

QB495-903 Descriptive astronomy

QB500.5-785 Solar system

QB799-903 Stars

QB980-991 Cosmogony. Cosmology
Subclass QC 

QC1-999 Physics

QC1-75 General

QC81-114 Weights and measures

QC120-168.85 Descriptive and experimental mechanics

QC170-197 Atomic physics. Constitution and properties of matter

Including molecular physics, relativity, quantum theory, and 

solid state physics 

QC221-246 Acoustics. Sound 

QC251-338.5 Heat 

QC310.15-319 Thermodynamics 

QC350-467 Optics. Light 

QC450-467 Spectroscopy 

QC474-496.9 Radiation physics (General) 

QC501-766 Electricity and magnetism 

QC501-(721) Electricity 

QC669-675.8 Electromagnetic theory 

QC676-678.6 Radio waves (Theory) 

QC701-715.4 Electric discharge 

QC717.6-718.8 Plasma physics. Ionized gases 

QC750-766 Magnetism 

QC770-798 Nuclear and particle physics. Atomic energy. Radioactivity 

QC793-793.5 Elementary particle physics 

QC794.95-798 Radioactivity and radioactive substances 

QC801-809 Geophysics. Cosmic physics 

QC811-849 Geomagnetism 

QC851-999 Meteorology. Climatology 

Including the earth's atmosphere 

QC974.5-976 Meteorological optics 

QC980-999 Climatology and weather 

QC994.95-999 Weather forecasting 
Subclass QD 

QD1-999 

QD1-65 

QD71-142 

QD146-197 

QD241-441 

QD415-436 

QD450-801 

QD625-655 

QD701-731 

QD901-999 

Chemistry 

General 

Including alchemy 

Analytical chemistry 

Inorganic chemistry 

Organic chemistry 

Biochemistry 

Physical and theoretical chemistry 

Radiation chemistry 

Photochemistry 

Crystallography 
Subclass QE 

QE1-996.5 Geology 

QE1-350.62 General 

Including geographical divisions 

QE351-399.2 Mineralogy 

QE420-499 Petrology 

QE500-639.5 Dynamic and structural geology 

QE521-545 Volcanoes and earthquakes 

QE601-613.5 Structural geology 

QE640-699 Stratigraphy 

QE701-760 Paleontology 

QE760.8-899.2 Paleozoology 

QE901-996.5 Paleobotany 
Subclass QH 

QH1-278.5 Natural history (General) 

QH1-(199.5) General 

Including nature conservation, geographical distribution 

QH201-278.5 Microscopy 

QH301-705.5 Biology (General) 

QH359-425 Evolution 

QH426-470 Genetics 

QH471-489 Reproduction 

QH501-531 Life 

QH540-549.5 Ecology 

QH573-671 Cytology 

QH705-705.5 Economic biology 
Subclass QK 

QK1-989 Botany 

QK1-474.5 General 

Including geographical distribution 

QK474.8-495 Spermatophyta. Phanerogams 

QK494-494.5 Gymnosperms 

QK495 Angiosperms 

QK504-(638) Cryptogams 

QK640-(707) Plant anatomy 

QK710-899 Plant physiology 

QK900-989 Plant ecology 
Subclass QL 

QL1-991 Zoology 

QL1-355 General 

Including geographical distribution 

QL360-599.82 Invertebrates 

QL461-599.82 Insects 

QL605-739.8 Chordates. Vertebrates 

QL614-639.8 Fishes 

QL640-669.3 Reptiles and amphibians 

QL671-699 Birds 

QL700-739.8 Mammals 

QL750-795 Animal behavior 

QL791-795 Stories and anecdotes 

QL799-799.5 Morphology 

QL801-950.9 Anatomy 

QL951-991 Embryology 
Subclass QM 

QM1-695 Human anatomy

QM1-511 General

QM531-549 Regional anatomy

QM550-577.8 Human and comparative histology

QM601-695 Human embryology
Subclass QP 

QP1-(981) Physiology 

QP1-345 General 

Including influence of the environment 

QP351-495 Neurophysiology and neuropsychology 

QP501-801 Animal biochemistry 

QP(901)-(981) Experimental pharmacology 
Subclass QR 

QR1-502 

QR1-74.5 

QR75-99.5 

QR99.6-99.8 

QR100-130 

QR171 

QR180-189.5 

QR355-502 

Microbiology 

General 

Bacteria 

Cyanobacteria 

Microbial ecology 

Microorganisms in the animal body 

Immunology 

Virology