DEXA 2004, the 15th International Conference on Database and Expert Systems Applications, was held August 30 ? September 3, 2004, at the University of Zaragoza, Spain. The quickly growing spectrum of database applications has led to the establisment of more specialized discussion platforms (DaWaK Conference, EC-Web Conference, EGOVConference, Trustbus Conference and DEXA Workshop: Every DEXA event has its own conference proceedings), which were held in parallel with the DEXA Conference also in Zaragoza. In your hands are the results of much effort. The work begins with the preparation of the...