Technology influences all art, and therefore all music, including composition, performance and listening. It always has, and it always will. For example, technical developments in materials, mechanics and manufacturing were important factors that permitted the piano to supersede the harpsichord as the primary concert Western keyboard instrument by about 1800. And with each new technical development new performance issues have been introduced. Piano performance technique is quite different from harpsichord technique, and composers responded to these differences with new music ideas and gestures. The multiple relationships between technology and composer and performer are dynamic and of paramount importance to each party. And a true consideration of any aspect of music requires that all three areas be examined. This has always been a part of music, and so these relationships are inherently important within computer music. The difference is that electronic technology has caused a fundamental change for all aspects of music, a difference that is as pivotal in the history of Western music as was the shift from oral to written preservation of music over a thousand years ago, and then also the accessibility provided by printed music five hundred years ago. In computer music, all parties are always acutely aware of the presence and influence of machine technology in both the visual and audible realms.