500 - Natural Sciences and Mathematics

   501 - Philosophy and theory
   502 - Miscellany
   503 - Dictionaries and encyclopedias
   504 - Unassigned
   505 - Serial publications
   506 - Organizations and management
   507 - Education, research, related topics
   508 - Natural history
   509 - Historical, geographic, persons treatment

510 - Mathematics

   511 - General principles of mathematics
   512 - Algebra, number theory
   513 - Arithmetic
   514 - Topology
   515 - Analysis
   516 - Geometry
   517 - Unassigned
   518 - Unassigned
   519 - Probabilities and applied mathematics

520 - Astronomy

   521 - Celestial mechanics
   522 - Techniques, equipment, materials
   523 - Specific celestial bodies and phenomena
   524 - Unassigned
   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 and related vibrations
   535 - Light and paraphotic phenomena
   536 - Heat
   537 - Electricity and electronics
   538 - Magnetism
   539 - Modern physics

540 - Chemistry and allied sciences

   541 - Physical and 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

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

570 - Life sciences, biology

   571 - Physiology and related subjects
   572 - Biochemistry
   573 - Specific systems in animals
   574 - Unassigned
   575 - Specific parts of and systems in plants
   576 - Genetics and evolution
   577 - Ecology
   578 - Natural history of organisms
   579 - Microorganisms, fungi, algae

580 - Plants

   581 - Specific topics in natural history
   582 - Plants noted for characteristics and flowers
   583 - Magnoliopsida (Dicotyledons)
   584 - Liliopsida (Monocotyledons)
   585 - Pinophyta (Gymnosperms)
   586 - Cryptogamia (Seedless plants)
   587 - Pteridophyta (Vascular seedless plants)
   588 - Bryophyta
   589 - Unassigned

590 - Animals

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

09.20.2005