This book constitutes the refereed proceedings of the Third International Conference on Knowledge Science, Engineering and Management, KSEM 2009, held in Vienna, Austria, in November 2009. The 42 revised full papers and 2 discussion panels presented were carefully reviewed and selected from numerous submissions for inclusion in the book. The papers provide new ideas and report state of the art research results in the broad areas of knowledge science, knowledge engineering, and knowledge management. Following two successful events in Guilin, People¿s Republic of China (KSEM 2006) and in Melbourne, Australia (KSEM 2007) the third event in this conference series was held for the first time in Europe, namely, in Vienna, Austria. KSEM 2009 aimed to be a communication platform and meeting ground for research on knowledge science, engineering and management, attracting high-quality, state-of-the-art publications from all over the world. It offers an exceptional opportunity for presenting original work, technological advances, practical problems and concerns of the research community. The importance of studying ¿knowledge¿ from different viewpoints such as science, engineering and management has been widely acknowledged. The accelerating pace of the "Internet age" challenges organizations to compress communication and innovation cycles to achieve a faster return on investment for knowledge. Thus, next-generation business solutions must be focused on supporting the creation of value by adding knowledge-rich components as an integral part to the work process. Therefore, an integrated approach is needed, which combines issues from a large array of knowledge fields such as science, engineering and management. Based on the reviews by the members of the Program Committee and the additional reviewers, 42 papers were selected for this year¿s conference. Additionally, two discussion panels dealing with ¿Knowware: The Third Star after Hardware and Software¿ and ¿Required Knowledge for Delivering Services¿ took place under the auspices of the conference. The papers and the discussions covered a great variety of approaches of knowledge science, management and engineering, thus making KSEM a unique conference.