Stefan born in 1961, attained a PhD in Historical Geology and Palaeontology
(at the University of Uppsala in 1990) and continued to work as an
earth-scientist for several years at the universities of G�teborg and
Copenhagen. These days he is living in G�teborg, Sweden, and teaches
mathematics for pupils at the age of 16 to 18. He still keeps an interest in
science in general, but especially in earth science and biology. Other
interests are online IQ-tests, psychology, sports and friendly discussions.