This chapter presents a novel approach to the development, integration, and operation of virtual enterprises (VEs). The approach is based on the idea of interactive models. An interactive model is a visual model of enterprise aspects that can be viewed, traversed, analyzed, simulated, adapted, and executed by the participants of the VE. The approach has been developed in several research projects, where experiences from industrial case studies are used as a basis for validation and further enhancement. A major result of this work is the model-driven infrastructure that integrates and supports VEs. The main innovative contributions of this infrastructure include concurrent modelling, metamodelling, management and performance of work, integrated support for ad hoc and structured processes, and customizable model- and process-driven integration.