Nowadays, digital information is relatively easy to capture and fairly inexpensive to store. The digital revolution has seen collections of data grow in size, and the complexity of the data therein increase. Question commonly arising as a result of this state of affairs is, having gathered such quantities of data, what do we actually do with it? It is often the case that large collections of data, however well structured, conceal implicit patterns of information that cannot be readily detected by conventional analysis techniques. Such information may often be usefully analyzed using a set of techniques referred to as knowledge discovery or data mining. These techniques essentially seek to build a better understanding of data, and in building characterizations of data that can be used as a basis for further analysis, extract value from volume.