New collaboration mechanisms and organizational forms supported by networking tools not only induce new business domains but "invade" all traditional sectors and organizations, which requires thinking of each business as part of a wider economic ecosystem and environment. The virtual enterprise / virtual organization developments, although initially technology-driven, are gathering more and more contributions of a multi-disciplinary nature, namely from the socio-economic and organizational areas. New behavioral forms, new cooperation agreements and social contracts, new liability agreements and risk negotiation practices, new ways of generating value for common developments, and correspondingly new challenges on intellectual property and ownership identification are among the major trends. This book contains selected articles from PRO-VE'02, the third working conference on Infrastructures for Virtual Enterprises, which was sponsored by the International Federation for Information Processing (IFIP) and held in Sesimbra, Portugal in May 2002. The included articles represent relevant examples of the current state of the art in virtual enterprises and other collaborative and networked organizations, and provide valuable insights on future trends and challenges. The book contents clearly reflect a growing maturation and diversification of the area. Important development directions are well represented, such as: modeling and reference architectures, formation of virtual organizations, including contract management and negotiation, operation support functionalities, infrastructures and interoperability, virtual communities and new collaboration forms, best practices and strategic planning, economic aspects and performance metrics, training and new ways of working. Collaborative Business Ecosystems and Virtual Enterprises is essential reading for researchers, engineers, managers, practitioners, sociologists, and students in production engineering, computer science, electrical engineering, mechanical engineering, organizational science, and industrial sociology.