Modem information technology has created new possibihties for more so phisticated and efficient control of supply chains. Most organizations can re duce their costs associated with the flow of materials substantially. Inventory control techniques are very important components in this development proc ess. A thorough understanding of relevant inventory models is a prerequisite for successful implementation. I hope that this book will be a useful tool in acquiring such an understanding. The book is primarily intended as a course textbook. It assumes that the reader has a good basic knowledge of mathematics and probability theory, and is therefore most suitable for industrial engineering and management science/operations research students. The book can be used both in under graduate and more advanced graduate courses. About fifteen years ago I wrote a Swedish book on inventory control. This book is still used in courses in production and inventory control at sev eral Swedish engineering schools and has also been appreciated by many practitioners in the field. Positive reactions from many readers made me contemplate writing a new book in English on the same subject. Encourag ing support of this idea from the Springer Editors Fred Hillier and Gary F- ven finally convinced me to go ahead with that project six years ago.