This book presents thoroughly arranged tutorial papers corresponding to lectures given by leading researchers at the Second International Summer School on Reasoning Web in Lisbon, Portugal, in September 2006. Building on the predessor school held in 2005 and published as LNCS 3564, the ten tutorial lectures presented provide competent coverage of current topics in semantic Web research and development.

The Portuguese Association for Artificial Intelligence hasbeen organizing Portuguese Conferences on ArtificialIntelligence, now held every second year, since 1985.This volume contains selected papers from the FifthConference on Artificial Intelligence. The conference has aninternational status: 62 contributions from 13 countrieswere received, of which 26 were from Portugal. To guaranteea high scientific standard, all the contributions werereviewed by at least three researchers, and only 20 paperswere accepted and included in these proceedings. The papersare organized into sections on...