MATHLAB is a computer algebra system created in 1964 by Carl Engelman at MITRE and written in Lisp.
Carl Engelman left MITRE for Symbolics where he contributed his expert knowledge in the development of Macsyma.
Abstract from DECUS Library Catalog: MATHLAB is an on-line system providing machine aid for the mechanical symbolic processes encountered in analysis.
It is capable of performing, automatically and symbolically, such common procedures as simplification, substitution, differentiation, polynomial factorization, indefinite integration, direct and inverse Laplace transforms, the solution of linear differential equations with constant coefficients, the solution of simultaneous linear equations, and the inversion of matrices.
[2] This application was developed as a plug-in for MATHLAB 68 (open-source), building on MATHLAB's linear algebra facilities (Laplace transforms, inverse Laplace transforms and linear algebra manipulation).