Peter Øhrstrøm, Professor of Information Science, Department of Communication and Psychology, Aalborg University, Denmark, has worked for many years with problems regarding formal representation of knowledge as well as problems within the history and philosophy of science. He is a doctor of philosophy (the history of ideas), and he is also a doctor of science (the history and philosophy of science). In his research he has studied philosophical and historical aspects of the ideas of reasoning, concepts of time and the use of various kinds of logic (such as tense logic, modal logic and deontic logic) for representing information and knowledge in a formal and useful manner. He has also been very interested in the use of information technology within the humanities. For several years, he was head of the study of Humanistic Informatics at Aalborg University. He is now a member of the editorial board of ICCS (the international conferences for conceptual structures), and he is the chairman of the Kaj Munk Research Centre, Aalborg University. He has been a partner in a number of Danish and European research projects. He is member of the Danish Ethical Council and of the board of representatives advicing The Danish Board of Technology.