Development of Semantic Web, with machine-readable content, has the potential to revolutionize the World Wide Web and its use. A Semantic Web Primer is the only book available on the Semantic Web to include a systematic treatment of different languages (XML, RDF, OWL, and rules) and technologies (explicit metadata, ontologies, and logic and inference) that are important for the Semantic Web development. After the introductory chapter, topics covered in subsequent chapters include XML and related technologies that support semantic interoperability; RDF and RDF Schema, the standard model data to machine-processable semantics, and OWL, the W3C-approved standards for the Web ontology language more extensive than RDF Schema; rules, both monotonic and nonmonotonic, in the framework of Semantic Web; selected application domain and how the Semantic Web would benefit them, the development of ontology-based system, and the current debate on key issues and predictions for the future.