# Library of Congress Classification/Class Q

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) | Science (General) |
| Q1-295 | General | General |
| Q300-390 | Cybernetics | Cybernetics |
| Q350-390 | | Information theory |
| QA1-939 | Mathematics | Mathematics | Mathematics |
| QA1-43 | General | General | General |
| QA47-59 | Tables | Tables | Tables |
| QA71-90 | Instruments and machines | Instruments and machines | Instruments and machines |
| QA75-76.95 | | Calculating machines | Calculating machines |
| QA75.5-76.95 | | Electronic computers. Computer science | Electronic computers. Computer science |
| QA76.75-76.765 | | | Computer software |
| QA101-(145) | Elementary mathematics. Arithmetic | Elementary mathematics. Arithmetic | Elementary mathematics. Arithmetic |
| QA150-272.5 | Algebra | Algebra | Algebra |
| QA273-280 | Probabilities. Mathematical statistics | Probabilities. Mathematical statistics | Probabilities. Mathematical statistics |
| QA299.6-433 | Analysis | Analysis | Analysis |
| QA440-699 | Geometry. Trigonometry. Topology | Geometry. Trigonometry. Topology | Geometry. Trigonometry. Topology |
| QA801-939 | Analytic mechanics | Analytic mechanics | Analytic mechanics |
| 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 |
| QC1-999 | Physics | Physics | Physics |
| QC1-75 | General | General | General |
| QC81-114 | Weights and measures | Weights and measures | Weights and measures |
| QC120-168.85 | Descriptive and experimental mechanics | Descriptive and experimental mechanics | Descriptive and experimental mechanics |
| QC170-197 | Atomic physics. Constitution and properties of matter Including molecular physics, relativity, quantum theory, and solid state physics | Atomic physics. Constitution and properties of matter Including molecular physics, relativity, quantum theory, and solid state physics | Atomic physics. Constitution and properties of matter Including molecular physics, relativity, quantum theory, and solid state physics |
| QC221-246 | Acoustics. Sound | Acoustics. Sound | Acoustics. Sound |
| QC251-338.5 | Heat | Heat | Heat |
| QC310.15-319 | | Thermodynamics | Thermodynamics |
| QC350-467 | Optics. Light | Optics. Light | Optics. Light |
| QC450-467 | | Spectroscopy | Spectroscopy |
| QC474-496.9 | Radiation physics (General) | Radiation physics (General) | Radiation physics (General) |
| QC501-766 | Electricity and magnetism | Electricity and magnetism | Electricity and magnetism |
| QC501-(721) | | Electricity | 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 | Magnetism |
| QC770-798 | Nuclear and particle physics. Atomic energy. Radioactivity | Nuclear and particle physics. Atomic energy. Radioactivity | Nuclear and particle physics. Atomic energy. Radioactivity |
| QC793-793.5 | | Elementary particle physics | Elementary particle physics |
| QC794.95-798 | | Radioactivity and radioactive substances | Radioactivity and radioactive substances |
| QC801-809 | Geophysics. Cosmic physics | Geophysics. Cosmic physics | Geophysics. Cosmic physics |
| QC811-849 | Geomagnetism | Geomagnetism | Geomagnetism |
| QC851-999 | Meteorology. Climatology Including the earth's atmosphere | Meteorology. Climatology Including the earth's atmosphere | Meteorology. Climatology Including the earth's atmosphere |
| QC974.5-976 | | Meteorological optics | Meteorological optics |
| QC980-999 | | Climatology and weather | Climatology and weather |
| QC994.95-999 | | | Weather forecasting |
| QD1-999 | Chemistry | Chemistry |
| QD1-65 | General Including alchemy | General Including alchemy |
| QD71-142 | Analytical chemistry | Analytical chemistry |
| QD146-197 | Inorganic chemistry | Inorganic chemistry |
| QD241-441 | Organic chemistry | Organic chemistry |
| QD415-436 | | Biochemistry |
| QD450-801 | Physical and theoretical chemistry | Physical and theoretical chemistry |
| QD625-655 | | Radiation chemistry |
| QD701-731 | | Photochemistry |
| QD901-999 | Crystallography | Crystallography |
| QE1-996.5 | Geology | Geology |
| QE1-350.62 | General Including geographical divisions | General Including geographical divisions |
| QE351-399.2 | Mineralogy | Mineralogy |
| QE420-499 | Petrology | Petrology |
| QE500-639.5 | Dynamic and structural geology | Dynamic and structural geology |
| QE521-545 | | Volcanoes and earthquakes |
| QE601-613.5 | | Structural geology |
| QE640-699 | Stratigraphy | Stratigraphy |
| QE701-760 | Paleontology | Paleontology |
| QE760.8-899.2 | Paleozoology | Paleozoology |
| QE901-996.5 | Paleobotany | Paleobotany |
| QH1-278.5 | Natural history (General) | Natural history (General) |
| QH1-(199.5) | | General Including nature conservation, geographical distribution |
| QH201-278.5 | | Microscopy |
| QH301-705.5 | Biology (General) | 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 |
| QK1-989 | Botany | Botany |
| QK1-474.5 | General Including geographical distribution | General Including geographical distribution |
| QK474.8-495 | Spermatophyta. Phanerogams | Spermatophyta. Phanerogams |
| QK494-494.5 | | Gymnosperms |
| QK495 | | Angiosperms |
| QK504-(638) | Cryptogams | Cryptogams |
| QK640-(707) | Plant anatomy | Plant anatomy |
| QK710-899 | Plant physiology | Plant physiology |
| QK900-989 | Plant ecology | Plant ecology |
| QL1-991 | Zoology | Zoology |
| QL1-355 | General Including geographical distribution | General Including geographical distribution |
| QL360-599.82 | Invertebrates | Invertebrates |
| QL461-599.82 | | Insects |
| QL605-739.8 | Chordates. Vertebrates | Chordates. Vertebrates |
| QL614-639.8 | | Fishes |
| QL640-669.3 | | Reptiles and amphibians |
| QL671-699 | | Birds |
| QL700-739.8 | | Mammals |
| QL750-795 | Animal behavior | Animal behavior |
| QL791-795 | | Stories and anecdotes |
| QL799-799.5 | Morphology | Morphology |
| QL801-950.9 | Anatomy | Anatomy |
| QL951-991 | Embryology | Embryology |
| QM1-695 | Human anatomy |
| QM1-511 | General |
| QM531-549 | Regional anatomy |
| QM550-577.8 | Human and comparative histology |
| QM601-695 | Human embryology |
| 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 |
| QR1-502 | Microbiology |
| QR1-74.5 | General |
| QR75-99.5 | Bacteria |
| QR99.6-99.8 | Cyanobacteria |
| QR100-130 | Microbial ecology |
| QR171 | Microorganisms in the animal body |
| QR180-189.5 | Immunology |
| QR355-502 | Virology |