This volume is concerned with the problems of finding optimal schedules for systems comprising several sequential machines. More specifically, attention is largely given in separate chapters to three classical processing systems: the flow shop, the job shop and the open shop. A final chapter deals with mixed graph problems. Each of the four chapters concludes with a comprehensive bibliography and review. The volume also has an introduction and finishes with an extensive reference section. This volume is suitable for researchers and graduate students of management science and operations research interested in production planning and flexible manufacturing.