Bernd Heine is Professor of African Studies (Afrikanistik) and Director of the Institute for African Studies at the University of Cologne in Germany. He has published thirty books, including Possession: Cognitive Sources, Forces, and Grammaticalization (1997), The Mukogodo Maasai: An Ethnobotanical Survey (co-author, 1994), Auxiliaries: Cognitive Forces and Grammaticalization (Oxford, 1993), and Grammaticalization: A Conceptual Framework (co-author, 1991).