Macsyma (Project MAC’s SYmbolic MAnipulator) is one of the oldest general purpose computer algebra systems which is still widely used. It was originally developed from 1968 to 1982 at MIT's Project MAC.
In 1982, Macsyma was licensed to Symbolics and became a commercial product. In 1992, Symbolics Macsyma was spun off to Macsyma, Inc., which continued to develop Macsyma until 1999. That version is still available for Microsoft's Windows XP operating system.
The 1982 version of MIT Macsyma remained available to academics and US government agencies, and it is distributed by the US Department of Energy (DOE). That version, DOE Macsyma, was maintained by Bill Schelter. Under the name of Maxima, it was released under GPL license in 1999, and remains under active maintenance.
The project was initiated in July, 1968 by Carl Engelman,William A. Martin (front end, expression display, polynomial arithmetic) and Joel Moses (simplifier, indefinite integration: heuristic/Risch). Bill Martin was in charge of the project until 1971, and Moses ran it for the next decade. Engelman and his staff left in 1969 to return to The MITRE Corporation. Some code came from earlier work, notably Knut Korsvold's simplifier. Later major contributors to the core mathematics engine were: Yannis Avgoustis (special functions), David Barton (solving algebraic systems of equations), Richard Bogen (special functions), Bill Dubuque (indefinite integration, limits, power series, number theory, special functions, functional equations, pattern matching, sign queries, Gröbner, TriangSys), Richard Fateman (rational functions, pattern matching, arbitrary precision floating-point), Michael Genesereth (comparison, knowledge database), Jeff Golden (simplifier, language, system), R. W. Gosper (definite summation, special functions, simplification, number theory), Carl Hoffman (general simplifier, macros, non-commutative simplifier, ports to Multics and LispM, system, visual equation editor), Charles Karney (plotting), John Kulp, Ed Lafferty (ODE solution, special functions), Stavros Macrakis (real/imaginary parts, compiler, system), Richard Pavelle (indicial tensor calculus, general relativity package, ordinary and partial differential equations), David A. Spear (Gröbner), Barry Trager (algebraic integration,factoring, Gröbner), Paul Wang (polynomial factorization and GCD, complex numbers, limits, definite integration, Fortran and LaTeX code generation), David Y. Y. Yun (polynomial GCDs), Gail Zacharias (Gröbner) and Rich Zippel (power series, polynomial factorization, number theory, combinatorics).