Broad subdivisions of Mathematics
Core branches of mathematics:
Applied and related areas:
Other organization schemes:
Areas not corresponding to MSC headings:
(Few index pages yet; sorry.)
[Note that the latest revision of the MSC was put into use for January
2000; not all pages at this site have been adapted yet.] 
Toplevel subject areas in the MSC

00:
General material including elementary mathematics

01:
History and biography

03:
Mathematical logic and foundations

05:
Combinatorics and graph theory

06:
Order, lattices, ordered algebraic structures

08:
General algebraic systems

11:
Number theory

12:
Field theory and polynomials

13:
Commutative rings and algebras

14:
Algebraic geometry

15:
Linear and multilinear algebra; matrix theory

16:
Associative rings and algebras

17:
Nonassociative rings and algebras

18:
Category theory, homological algebra

19:
Ktheory

20:
Group theory and generalizations

22:
Topological groups, Lie groups

26:
Real functions and elementary calculus

28:
Measure and integration

30:
Functions of a complex variable

31:
Potential theory

32:
Several complex variables and analytic spaces

33:
Special functions including trigonometric functions

34:
Ordinary differential equations

35:
Partial differential equations

37:
Dynamical systems and ergodic theory

39:
Difference and functional equations

40:
Sequences, series, summability

41:
Approximations and expansions

42:
Fourier analysis

43:
Abstract harmonic analysis

44:
Integral transforms, operational calculus

45:
Integral equations

46:
Functional analysis

47:
Operator theory

49:
Calculus of variations and optimal control; optimization

51:
Geometry, including classic Euclidean geometry

52:
Convex and discrete geometry

53:
Differential geometry

54:
General topology

55:
Algebraic topology

57:
Manifolds and cell complexes

58:
Global analysis, analysis on manifolds

60:
Probability theory and stochastic processes

62:
Statistics

65:
Numerical analysis

68:
Computer science

70:
Mechanics of particles and systems

74:
Mechanics of deformable solids

76:
Fluid mechanics

78:
Optics, electromagnetic theory

80:
Classical thermodynamics, heat transfer

81:
Quantum Theory

82:
Statistical mechanics, structure of matter

83:
Relativity and gravitational theory

85:
Astronomy and astrophysics

86:
Geophysics

90:
Operations research, mathematical programming

91:
Game theory, economics, social and behavioral sciences

92:
Biology and other natural sciences

93:
Systems theory; control

94:
Information and communication, circuits

97:
Mathematics education
