Progress in collaborative networks continues showing a growing number of manifestations and has led to the acceptance of Collaborative Networks (CN) as a new scientific discipline. Contributions to CN coming from multiple reference disciplines has been extensively investigated. In fact developments in CN have benefited from contributions of multiple areas, namely computer science, computer engineering, communications and networking, management, economy, social sciences, law and ethics, etc. Furthermore, some theories and paradigms defined elsewhere have been suggested by several research groups as promising tools to help define and characterize emerging collaborative organizational forms. Although still at the beginning of a long way to go, there is a growing awareness in the research and academic world, for the need to establish a stronger theoretical foundation for this new discipline and a number of recent works are contributing to this goal. From a utilitarian perspective, agility has been pointed out as one of the most appealing characteristics of collaborative networks to face the challenges of a fast changing socio-economic context. However, during the last years it became more evident that finding the right partners and establishing the necessary preconditions for starting an effective collaboration process are both costly and time consuming activities, and therefore an inhibitor of the aimed agility. Among others, obstacles include lack of information (e.g. non-availability of catalogs with normalized profiles of organizations) and lack of preparedness of organizations to join the collaborative process. Overcoming the mismatches resulting from the heterogeneity of potential partners (e.g. differences in infrastructures, corporate culture, methods of work, and business practices) requires considerable investment. Building trust, a pre-requisite for any effective collaboration, is not straight forwardand requires time. Therefore the effective creation of truly dynamic collaborative networks requires a proper context in which potential members are prepared to rapidly get engaged in collaborative processes. The concept of breeding environment has thus emerged as an important facilitator for wider dissemination of collaborative networks and their practical materialization. The PRO-VE'05 held in Valencia, Spain, continues the 6th event in a series of successful working conferences on virtual enterprises. This book includes selected papers from that conference and should become a valuable tool to all of those interested in the advances and challenges of collaborative networks.