This volume collects the papers selected for presentation at the IX Congress of the Italian Association for Arti?cial Intelligence (AI*IA), held in Milan at the University of Milano-Bicocca (September 21-23, 2005). On the one hand this congress continues the tradition of AI*IA in organizing its biannual s- enti?c meeting from 1989; on the other hand, this edition is a landmark in the involvement of the international community of arti?cial intelligence (AI), directly involving a broad number of experts from several countries in the P- gramCommittee. Moreover, the peculiar nature of scienti?c...