“The Semantic Web lies at the heart of Tim Berners-Lee’s vision for the future of the World Wide Web. Along with others at the W3C Berners-Lee is working on the infrastructure for this next stage of the Web’s life. But the question ‘What is the Semantic Web?’ is being asked with increasing frequency. While mainstream media is content with a high level view, XML developers want to know more, and they want to discover the substance behind the vision.”