This document enables the advancement of interoperability from the data/information exchange paradigm to knowledge sharing at decreasing level of abstraction, starting at IT concept level (semantic coordination) through business domain concept level (agreed service function level cooperation), domain level (cross-domain cooperation) up to individual context (skills-based end-user collaboration). The document defines a model and framework for a harmonized representation of existing or intended systems with a specific focus on ICT-supported business systems. The Interoperability and Integration Reference Architecture supports ontology harmonization or knowledge harmonization to enable interoperability between, and integration of, systems, standards and solutions at any level of complexity without the demand for continuously adapting/revising those specifications. The approach can be used for analysing, designing, integrating, and running any type of systems. For realizing advanced interoperability, flexible, scalable, business-controlled, adaptive, knowledge-based, intelligent health and social ecosystems need to follow a systems-oriented, architecture-centric, ontology-based and policy-driven approach.The languages for representing the different views on systems such as ontology languages like Common Logic (CL) (ISO/IEC 24707) and Web Ontology Language (OWL) – specifically OWL 2 (World Wide Web Consortium (W3C®), languages for modeling and integrating business processes like Business Process Modeling Language (BPML) (OMG®), but also OMG’s Unified Modeling Language (UML, also specified as ISO/IEC 19505) based representation styles for the different ISO/IEC 10746 (all parts) views are outside the scope of this document.