This book constitutes the refereed proceedings of the 5th International Conference on Discovery Science, DS 2002, held in Lubeck, Germany, in November 2002. The 17 revised full papers and 27 revised short papers presented together with 5 invited contributions were carefully reviewed and selected from 76 submissions. The papers are organized in topical sections on applications of discovery science to natural science, knowledge discovery from unstructured and semi-structured data, metalearning and analysis of machine learning algorithms, combining machine learning algorithms, neural networks and statistical learning, new approaches to knowledge discovery, and knowledge discovery from text.