Maintenance is as an essential factor that can lead to the reduction of "inefficiencies" and has to be considered as a well-established Enterprise Domain and as a profit centre. The development of optimized maintenance strategies may have great impacts not only on the equipment availability and cost optimization, but also on the product quality, environment protection, human safety, energy control, zero waste and enterprise strategy. This e-book is dedicated to research papers dealing with maintenance issues. It includes four papers meticulously selected from the 6th International Conference on Industrial Engineering and Production Management (IEPM’03)