Life without the World Wide Web has become unthinkable, much like life without electricity or water supply. We rely on the web to check public transport schedules, buy a ticket for a concert or exchange photos with friends. However, many everyday tasks cannot be accomplished by the computer itself, since the websites are designed to be read by people, not machines. In addition, the online information is often unstructured and poorly organized, leaving the user with tedious work of searching and filtering. This book takes us to the frontiers of the emerging Web 3.0 or Semantic Web - a new generation of web aimed at bridging this gap and making the web experience accessible and easy. The Semantic Web is a vision of online information that can be readily interpreted and analyzed by machines, adapting it to user's needs and abilities.