The development of the Semantic Web, with machine-readable content, has the potentialto revolutionize the World Wide Web and its uses. A Semantic Web Primer providesan introduction and guide to this continuously evolving field, describing its key ideas, languages,and technologies. Suitable for use as a textbook or for independent study by professionals, itconcentrates on undergraduate-level fundamental concepts and techniques that will enable readers toproceed with building applications on their own and includes exercises, project descriptions, andannotated references to relevant online materials. The third edition of thiswidely used text has been thoroughly updated, with significant new material that reflects a rapidlydeveloping field. Treatment of the different languages (OWL2, rules) expands the coverage of RDF andOWL, defining the data model independently of XML and including coverage of N3/Turtle and RDFa. Achapter is devoted to OWL2, the new W3C standard. This edition also features additional coverage ofthe query language SPARQL, the rule language RIF and the possibility of interaction between rulesand ontology languages and applications. The chapter on Semantic Web applications reflects the rapiddevelopments of the past few years. A new chapter offers ideas for term projects. Additionalmaterial, including updates on the technological trends and research directions, can be found at.