This book contains most of the papers presented at the Sixth International Conference on Data Mining held in Skiathos, Greece. Twenty-five countries from all the continents are represented in the papers published in the book, offering a real multinational and multicultural range of experiences and ideas. There has been an explosion of interest in data mining applications to unstructured data and this is reflected in a large increase in text mining. Consequently it is not difficult to forecast that in the next months several applications will appear dedicated to analysis of content coming from the billions of available web pages, newsgroups, emails, chat lines and message boards, and that the interest in unstructured data mining and text mining will grow amongst researchers, OEM and system integrators working in sectors as information retrieval, semantic web, linguistics, and knowledge management. In business applications, the most promising areas are those regarding National Security, Competitive Intelligence and Customer Relationship Management. They can all be incorporated into the area of Intelligence Analysis, of especial interest for textual data mining and text mining applications. Contents include: Data mining; Text mining; Neural networks and decision trees; Link analysis; Clustering and categorization; Consumer and strategic intelligence; Applications in science, engineering and life sciences, and Applications in business, industry and government.