Extant, extinct, and proposed systems for performing interactive mathematics are surveyed, with special attention to those systems with graphical output. The systems are grouped as general purpose graphical, special purpose graphical, and other systems of interest. The solution of a least squares data-fitting problem by the various general purpose graphical systems is then compared to the solution of the same problem by PEG, a special purpose graphmal system for interactive least squares data-fitting, written at the Stanford Linear Accelerator Center. A summary inelude~ a discussion of many of the references that appear in the fairly comprehensive bibliography.