This research will involve the formulation, analysis and computational solution of several fundamental mathematical models of production and inventory systems. Two critical managerial issues will be addressed: (1) Inventory control in a fluctuating environment. This topic includes inventory management for products subject to technological obsolescence and for new products, accounting for supply uncertainties, and coping with fluctuating interest rates. New models and new methods will be developed to handle these pervasive phenomena. (2) Coordination of procurement and production activities. Here focus is on the problems arising from the need to manage many different products in concert and from two additional sources of complexity, uncertain demands and capacity limits. Specifically, methods will be developed for managing the joint procurement of multiple products under uncertain demand, and for production scheduling when several products share a group of machines.