The Lisp interface to Jack will allow general programming of Jack internals and should simplify all forms of Jack development. It will be distributed with Jack-5.7 and will allow users without source code to extend or modify Jack, and users with source code to have a high-level, object-oriented, interactive prototyping environment. After prototyping in lisp, developers can rewrite their code in C++ if speed is crucial, otherwise, code can be left in lisp to simplify maintenance and to insure upward compatibility with future Jack versions.