The papers in this volume comprise the refereed proceedings of the conference ' Artificial Intelligence in Theory and Practice' (IFIP AI 2008), which formed part of the 20th World Computer Congress of IFIP, the International Federation for Information Processing (WCC-2008), in Milan, Italy in September 2008. The conference is organised by the IFIP Technical Committee on Artificial Intelligence (Technical Committee 12) and its Working Group 12.5 (Artificial...