This book is about knowledge, it is about the externalization of human kno- edge and about all the attempts we are undertaking to access what we have externalized before. Thus, the book should be of interest to a wide audience. Ontheotherhand, therearebooksaboutknowledge, knowledgemanagement and the like galore. There is an even larger ?ood of journal articles, conference papers andtechnicalreports, but it is rumoredthatmostare notreadby anyone at all. So, why read the present book or, at least, some of its papers? In my opinion, it is the idea of memetics which makes these proceedings special. Not every contribution deals with memetics, but Tanaka's work and his current projects are carving out the pro?le of what you ?nd in the book. Let's have a closer look. Richard Dawkins in his book The Sel?sh Gene, 1976 coined the term meme; thetermisestablishednow.TheOxfordEnglish Dictionarysays: 'meme(mi: m), n. Biol. (shortened from mimeme ... that which is imitated, after GENE n.) An element of a culture that may be considered to be passed on by non-genetic means, esp. imitation'. Yuzuru Tanaka has seized upon Dawkin's suggestion and extended it - wardsconceptsand implementationsthat setthe stagefor non-geneticevolution in computer and network environments. He has coined the term meme media. His comprehensive book Meme Media and Meme Market Architectures, 2003 summarizes the current state of a?airs from the perspecive of information and communication technologies.

This book constitutes the refereed proceedings of the 6th International Conference on Discovery Science, DS 2003, held in Sapporo, Japan in October 2003.

The 18 revised full papers and 29 revised short papers presented together with 3 invited papers and abstracts of 2 invited talks were carefully reviewed and selected from 80 submissions. The papers address all current issues in discovery science including substructure discovery, Web navigation patterns discovery, graph-based induction, time series data analysis, rough sets, genetic algorithms, clustering, genome analysis, chaining patterns, association rule mining, classification, content based filtering, bioinformatics, case-based reasoning, text mining, Web data analysis, and more.