This reference text discusses models and analyzes cases that are useful for material requirements planning (MRP), just-in-time (JIT) environments and supply chain environments, as well as traditional production-inventory systems. It covers important concepts, including production-inventory systems, optimal purchase quantity, optimal production quantity, instantaneous procurement, multiple input items, sensitivity analysis, multiproduct manufacturing, determination of optimum cycle time, fractional backlogging, and incorporating input item procurement and flexibility in the production rate. Aimed at senior undergraduate and graduate students, and professionals in the field of industrial engineering, production engineering and manufacturing science, this text: Provides detailed models/analysis pertaining to various cases which are useful for material requirements planning and supply chain environments Elaborates manufacturing rate flexibility, demand variation and production rate variation Discusses the multi-item manufacturing environment and presents models with backorders, as well as fractional backlogging Analyzes flexible production rates, along with upward and downward variations.