ZQC is based on the principle that defects are prevented by controlling the performance of a process so that it cannot produce defects, even when a mistake is made by the machine or a human operator. Instead of pointing fingers at people, ZQC findsways to keep errors from turning into defects. This book introduces front-line workers to the basic methodology of ZQC in a succinct, easy to read format that covers all aspects of this important manufacturing improvement strategy.