This volume contains the papers presented at the Fifth International Symposium on Foundations of Information and Knowledge Systems (FoIKS 2008) which was held in Pisa, Italy during February 11–15, 2008. On behalf of the Program Committee we commend these papers to you and hope you find them useful. The FoIKS symposia provide a biennial forum for presenting and discussing theoretical and applied research on information and knowledge systems. The goal is to bring together researchers with an interest in this subject, share research experiences, promote collaboration and identify new issues and directions for future research.
