Although the Web is growing at an astounding pace, surpassing the 8 billion page mark, most pages are still designed for human consumption and cannot be processed by machines. Computers are used to display the information, but human intervention is still required to interpret the results. The Semantic Web unleashes a revolution of new possibilities in which content is given formal, machine processable semantics. This book provides a well-paced introduction to the Semantic Web. It covers a wide range of topics, from new trends (ontologies, rules) to existing technologies (Web Services and software agents) to more formal aspects (logic and inference). It includes: real-world (and complete) examples of the application of Semantic Web concepts; how the technology presented and discussed throughout the book can be extended to other application areas, i.e. Geographic Information Sciences, Bioinformatics and Fine Arts.