This book constitutes the refereed proceedings of the First International Conference on Web Reasoning and Rule Systems, RR 2007, held in Innsbruck, Austria in June 2007 as a merger of the three previously separate events: International Workshop on Principles and Practice of Semantic Web Reasoning (PPSWR), the International Conference on Rules and Rule Markup Languages for the Semantic Web (RuleML), and the International Workshop on Reasoning on the Web (RoW).

The 14 revised full papers, 15 revised short papers presented together with 7 poster papers were carefully reviewed and selected from over 60 submissions. The papers address all current topics in Web reasoning and rule systems such as acquisition of rules and ontologies by knowledge extraction, design and analysis of reasoning languages, implemented tools and systems, standardization, ontology usability, ontology languages and their relationships, rules and ontologies, reasoning with uncertainty, reasoning with constraints, rule languages and systems, semantic Web services modeling and applications.