This textbook presents models and solutions in inventory management. It begins with a "must-read" chapter discussing basic terminology, concepts, taxonomy, and tenets of inventory system and common mathematical assumptions underlying the models. With a systematic organization, it then presents various models such as the EOQ model, lot-sizing models, Newsvendor model, periodic review models with variable and fixed ordering cost, and a continuous time model. Additionally, it discusses methods in multiechelon systems. In summary it tries to establish relationships between the dicussed models and real situations and discusses some examples in detail. Not directly competitive with other textbooks in this field, (more mathematical than some, less than others) this graduate textbook will appeal to senior and first year graduate students in operations research, industrial engineering, and quantitative MBA programs and can also serve as a reference to persons in the industry.