William Frederick Schelter (1947[1] – July 30, 2001) was a professor of mathematics at The University of Texas at Austin and a Lisp developer and programmer. Schelter is credited with the development of the GNU Common Lisp (GCL) implementation of Common Lisp and the GPL'd version of the computer algebra system Macsyma called Maxima. Schelter authored Austin Kyoto Common Lisp (AKCL) under contract with IBM.