Current Semantic Web reasoning systems do not scale to the requirements of their promising and interesting applications such as analyzing data from millions of mobile devices, dealing with terabytes of scientific data, and content management in enterprises with thousands of knowledge workers. Therefore, a novel approach is required that goes beyond the current paradigms strictly based on logic: a possible approach is Stream Reasoning, an unexplored yet potentially high impact research area, arising from the application of certain results obtained by the Data Streams community to the Semantic Web and reasoning domains. Aim of this book is to present C-SPARQL, a new language that builds on top of SPARQL adding support for RDF streams and SQL-like aggregates, which represent a first step toward Stream Reasoning and a new paradigm of reasoning.