This book is concerned with hierarchical control of manufacturing systems under uncertainty.  It focuses on system performance measured in long-run average cost criteria, exploring the relationship between control problems with a discounted cost and that with a long-run average cost in connection with hierarchical control.  A new theory is articulated that shows that hierarchical decision making in the context of a goal-seeking manufacturing system can lead to a near optimization of its objective.  The approach in the book considers manufacturing systems in which events occur at different time scales.