Since 1989 Dieter Fensel is working as a scientist at the University of Karlsruhe. He holds a Diploma in computer science from the Technical University of Berlin and a Diploma in social science from the Free University of Berlin. He received his Ph.D. in economic science from the University of Karlsruhe in 1993. His thesis was concerned with the development of the Knowledge Acquisition and Representation Language KARL. He developed the modelling primitives and the formal (i.e., declarative) semantics of KARL. Currently, he is working on reuse of formal specifications and use of formal specifications for reuse. Further activities are concerned with the development and application of machine learning algorithms.