Interoperability of enterprises is one of the main requirements for economical and industrial collaborative networks. Enterprise interoperability (EI) is based on the three domains: architectures and platforms, ontologies and enterprise modeling. This book presents the EI vision of the “Grand Sud-Ouest” pole (PGSO) of the European International Virtual Laboratory for Enterprise Interoperability (INTEROP-VLab). It includes the limitations, concerns and approaches of EI, as well as a proposed framework which aims to define and delimit the concept of an EI domain. The authors present the basic concepts and principles of decisional interoperability as well as concept and techniques for interoperability measurement. The use of these previous concepts in a healthcare ecosystem and in an extended administration is also presented.