Issues in synthesis performance practice are too numerous to try to summarize here. The reader is referred to the survey chapter by Gareth Loy . Suffice it to say that the musical control of digital musical instruments is still in its infancy despite some good work on the problems. Perhaps the problem can be better appreciated by considering that instruments made of metal and wood are played by human hands; therefore, to transfer past excellence in musical performance to new digital instruments requires either providing an interface for a human performer--a growing trend--or providing a software control layer that ``knows'' a given musical context. The latter is an artificial intelligence problem.