Introduction.- Part I System Integration, Ontologies, and User Interfaces.- Application Integration on the User Interface Level.- Ontology-based System Integration.- Ontologies in User Interface Development.- Part II Integrating User Interfaces with Ontologies.- A Framework for User Interface Integration.- An Ontology of User Interfaces and Interactions.- Data Object Exchange.- Efficient Semantic Event Processing.- Crossing Technological Borders.- Part III The Future of Ontology-based UI Integration.- Improving Information Exploration.- Towards End-user User Interface Integration.- Conclusion and Outlook.- Index.