Christian Freksa is briefly visiting the Center for Spatial Studies, at 3512 Phelps Hall. Freksa holds the Chair of Cognitive Systems at the Faculty of Mathematics and Informatics at the University of Bremen, Germany. His research concerns representation and reasoning with incomplete, imprecise, lean, coarse, approximate, fuzzy, and conflicting knowledge about physical environments. Particular emphasis is on qualitative spatial and temporal reasoning. Freksa received a Ph.D. in Artificial Intelligence from UC Berkeley. He carried out research at the Max Planck Institute and at the Technical University of Munich, at the International Computer Science Institute in Berkeley, and at the University of Hamburg. In 2002 he initiated the International Spatial Cognition Quality Network and the Spatial Cognition Research Center in Bremen and Freiburg that he has directed since 2003. Christian Freksa is a Fellow of the European AI society ECCAI.