Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online.One of the most challenging problems of the information society is dealing with the increasing data overload. Due to the digitalization of all sorts of content and due to the improvement and drop in cost of recording technologies, the amount of available information is enormous and is increasing exponentially. It has thus become important for companies, governments and individuals to be able to discriminate information from noise, detecting those data that are useful or interesting. The development of profiling technologies must be seen against this background. These technologies are thought to efficiently collect and analyse data in order to find or test knowledge in the form of statistical patterns between data. This process is called Knowledge Discovery in Databases (KDD) (Fayyad, Piatetsky-Shapiro & Smyth 1996), which provides the profiler with sets of correlated data that are used as profiles .