Over the last decade, professionals in the various reservoir disciplines have learned to work together and strive for synergy. They have created multidisciplinary teams and organized common working environments where they compile integration databases, design interoperable applications, and share earth models. This process of integration generates extra value. When applied to reservoir studies, the integration process can help foster more effective, less expensive projects. What, however, does integration really mean, under everyday working conditions? Which new technical and professional challenges must be faced? What kind of changes does it imply for traditional ways of working? What is the role of the project leader in the integration process? The goal of this book is to provide some answers to these questions, and to highlight the critical differences between an integrated reservoir study and a traditional one.