This course presents the main concepts of integrated packaged software systems that are used as the backbone of order management in almost all large companies. The main functionalities of ERP systems are based on previous concepts of MRP ("Material Requirements Planning") and MRP II ("Manufacturing Resource Planning"). The functionalities of these logistical systems are explained and the reasons for the importance of ERP systems are discussed. The market for ERP systems is outlined and the widely implemented SAP R/3 system is used to demonstrate certain functionalities of ERP systems.