The area of Virtual Organizations as a main component of the new discipline of Collaborative Networks has been the focus of research globally. The fast evolution of the information and communication technologies and in particular the so-called Internet technologies, also represents an important motivator for the emergence of new forms of collaboration. However, the research in many of these cases is highly fragmented, considering that each project is focused on solving specific problems. As such, there is no effective consolidation/ harmonization among them in order to have an effective impact and facilitate the interaction among the involved experts. This book represents a contribution to the consolidation of the already vast amount of empirical knowledge and practical experience. A synthesis of results collected from the analysis of numerous projects and industry case studies is presented, with focus on: Principles and models, ICT infrastructures and tools, Implementation issues, and Case studies.