Dewey Decimal System: 21st edition
000 | 100 | 200 | 300 | 400 | 500 | 600 | 700 | 800 | 900



500 Natural sciences & mathematics
501 Philosophy & theory
502 Miscellany
503 Dictionaries & encyclopedias
504 Not assigned or no longer used
505 Serial publications
506 Organizations & management
507 Education, research, related topics
508 Natural history
509 Historical, areas, persons treatment

510 Mathematics
511 General principles
512 Algebra & number theory
513 Arithmetic
514 Topology
515 Analysis
516 Geometry
517 Not assigned or no longer used
518 Not assigned or no longer used
519 Probabilities & applied mathematics

520 Astronomy & allied sciences
521 Celestial mechanics
522 Techniques, equipment, materials
523 Specific celestial bodies & phenomena
524 Not assigned or no longer used
525 Earth (Astronomical geography)
526 Mathematical geography
527 Celestial navigation
528 Ephemerides
529 Chronology

530 Physics
531 Classical mechanics Solid mechanics
532 Fluid mechanics Liquid mechanics
533 Pneumatics (Gas mechanics)
534 Sound & related vibrations
535 Light & paraphotic phenomena
536 Heat
537 Electricity & electronics
538 Magnetism
539 Modern physics

540 Chemistry & allied sciences
541 Physical & theoretical chemistry
542 Techniques, equipment, materials
543 Analytical chemistry
544 Qualitative analysis
545 Quantitative analysis
546 Inorganic chemistry
547 Organic chemistry
548 Crystallography
549 Mineralogy

550 Earth sciences
551 Geology, hydrology, meteorology
552 Petrology
553 Economic geology
554 Earth sciences of Europe
555 Earth sciences of Asia
556 Earth sciences of Africa
557 Earth sciences of North America
558 Earth sciences of South America
559 Earth sciences of other areas

560 Paleontology Paleozoology
561 Paleobotany, fossil microorganisms
562 Fossil invertebrates
563 Other fossil invertebrates
564 Fossil Mollusca & Molluscoidea
565 Fossil Arthropoda
566 Fossil Chordata
567 Fossil cold-blooded vertebrates
568 Fossil Aves (Fossil birds)
569 Fossil Mammalia

570 Life sciences
571 Physiology & related subjects
572 Biochemistry
573 Specific systems in animals
574 Not assigned or no longer used
575 Specific parts of and systems in plants
576 Evolution & genetics
577 Ecology
578 Natural history of organisms
579 Microorganisims, fungi, algae

580 Plants
581 Specific topics in natural history
582 Plants noted for characteristics & flowers
583 Magnoliopsida (Dicotyledons)
584 Liliopsida (Monocotyledons)
585 Pinophyta (Gymnosperms) Coniferales
586 Cryptogamia (Seedless plants)
587 Pteridophyta (Vascular seedless plants)
588 Bryophyta
589 Not assigned or no longer used

590 Animals
591 Specific topics in natural history
592 Invertebrates
593 Marine & seashore invertebrates
594 Mollusca & Molluscoidea
595 Arthropoda
596 Chordata
597 Cold-blooded vertebrates Fishes
598 Aves (Birds)
599 Mammalia (Mammals)