The Architecture of Interoperable Information Systems (AIOS) is a reference architecture for the development of interoperable enterprise information systems. If enterprises or public administrations want to engage in automated business processes with other organizations, their IT systems must be able to work together, i.e. they need to be interoperable. The AIOS represents a generic building plan for these organizations to develop interoperable information systems by systematically adjusting and extending their internal information systems.The AIOS was described in a doctoral thesis and is based on the results of various research projects on interoperability. It is independent from specific products or vendors but describes generically the different layers, views, relationships and technic