Experts in operations research and developers of software application systems have been treading separate paths for many years. It is urgently necessary to reset this course so that the demanding requirements of variousCIM concepts can be realized. This is specially relevant for computer-based stock management. Both authors, with a number of years of practical experience behind them, have written this book with this objective in mind. The book shows how modern inventory control can be rationally structured with the help of OR. Two aspects are given importance:1) the necessary mathematical derivations are completely explained in detail so that the reader will be able to optimally handle a given situation with the help of the methods learned in this book, and 2) aside from the models, strong emphasis is given on numerical methods. Suitable algorithms are thoroughly explained for the more important cases.