Common Lisp (Steele 1990) and the Common Lisp Object System (Bobrow 1988) provide an environment uniquely suited to the exploratory and incremental process of musical composition. Common Music is a high-level music composition language built in Common Lisp and CLOS designed to support computer composition in a variety of score formats through a common protocol. Initially prototyped on a Symbolics Lisp machine, the system runs under most Common Lisp environments found on standard computers such as Apple Macintosh and NeXT machines. Common Music is currently offered at CCRMA as part of course work for computer music classes and workshops. It is available through anonymous file transfer (ftp) on the machine ccrma-ftp in the file named /pub/cm.tarfile.Z