MATHLAB is a computer algebra system created in 1964 by Carl Engelman at MITRE and written in Lisp.
"MATHLAB 68" was introduced in 1967[1] and became rather popular in university environments running on DECs PDP-6 and PDP-10 under TOPS-10 or TENEX. In 1969 this version was included in the DECUS user group's library (as 10-142) as royalty-free software.
Carl Engelman left MITRE for Symbolics where he contributed his expert knowledge in the development of Macsyma.