European Healthcare Systems are facing a difficult period characterized by increasing costs and spending cuts due to economic problems. More than ever, it is important to converge the goals of management and clinical staff through the use of tools which can facilitate effective decision making and the enforcement of measures to improve the efficiency and effectiveness of hospital services in order to make sustainable the whole system. Economy-related studies show that the operating room is the most costly unit of a hospital. Therefore attempts at improving services centred around the OR block would have a big impact on overall hospital performance. The primary goal of the ORM approach described in this book was to create a practical and user-friendly data processing tool, providing hospital managers, anesthesiologists and surgeons with clear information regarding performance.