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 Intelligence Applications). All papers were reviewed by at least two members of our Program Committee. Final decisions were made by the...