Book excerpt: Vibration and noise reduce the perceived quality, productivity, and efficiency of many and limit production speeds electromechanical systems. Vibration can cause defects during manufacturing and produce premature failure of finished products due to fa tigue. Potential contact with a vibrating system or hearing darnage from a noisy machine can produce a dangerous, unhealthy, and uncomfortable operating environ ment. Recent advances in computer technology have allowed the development of so phisticated electromechanical systems for the control of vibration and noise. The demanding specifications of many modern systems require higher performance than possible with the traditional, purely mechanical approaches of increasing system stiff ness or damping. Mechatronic systems that integrate computer software and hard ware with electromechanical sensors and actuators to control complex mechanical systems have been demonstrated to provide outstanding vibration and noise reduc tion. The current trends toward higher speed computation and lower cost, higher performance sensors and actuators indicate the continuing possibilities for this con trol approach in future applications.