Abstract: An interactive music composition and performance system is a real-time composing and sound-producing system which employs a synthesizer, a programmable computer, and at least one performance device and which functions automatically to generate controls which determine the course of the musical composition it plays as well as the nature of the sound it produces. The system is interactive in that a user can direct aspects of the system's production of music, as he or she hears it being produced, by use of a performance device. If the user does not provide an input, the system proceeds automatically to compose music and produce sound.