Abstract
In this paper we present results from the ATHENA Integrated Project in defining the ATHENA Interoperability Framework (AIF) for enterprise applications and software systems. The AIF provides a compound framework and associated reference architecture for capturing the research elements and solutions to interoperability issues that address the problem in a holistic way. The AIF also provides an associated methodological framework which describes the approach towards interoperability from the decision to evaluate collaboration until solution maintenance, and the reference guidelines for the adoption of the reference architecture.