Processes and Foundations for Virtual Organizations contains selected articles from PRO-VE’03, the Fourth Working Conference on Virtual Enterprises, which was sponsored by the International Federation for Information Processing (IFIP) and held in Lugano, Switzerland in October 2003. This fourth edition includes a rich set of papers revealing the progress and achievements in the main current focus areas: -VO breeding environments; -Formation of collaborative networked organizations; -Ontologies and knowledge management; -Process models and interoperability; -Infrastructures; -Multi-agent approaches. In spite of many valid contributions in these areas, many research challenges remain. This is clearly stated in a number of papers suggesting a new research agenda and strategic research roadmaps for advanced virtual organizations. With the selected papers included in this book, PRO-VE pursues its double mission as a forum for presentation and discussion of achievements as well as a place to discuss and suggest new directions and research strategies.