Most organisations use, transform, distribute or sell materials of one or several kinds. The management of materials has serious implication on the financial, production, and marketing functions of an organisation. As the level of complexity of a product increases, so does the importance of managing materials. To fulfil their role in providing products and services, enterprises must satisfy the needs of production, as well as services through the use of all resources such as labour, capital, equipment and materials. All these managerial activities are called materials management. This book covers the topic of inventory systems.