My main research interests are in devising computer models of the human mind regarding spatial knowledge processing, in issues of knowledge representation in human memory, and in spatial mental models and mental imagery. Besides pursuing basic research in spatial cognition I apply results obtained in the SFB/TR 8 project R1-[ImageSpace] in intelligent assistance systems. These systems may provide help to people coping with cognitively demanding spatial tasks as they are found, for instance, in the field of architectural design.