Pertti Ahonen is Professor of History in the Department of History and Ethnology at the University of Jyv skyl , Finland. He is the author of "After the Expulsion: West Germany and Eastern Europe 1945-1990" (2003), "People on the Move: Forced Population Movements in Europe in the Second World War and Its Aftermath" (co-authored with Gustavo Corni, Jerzy Kochanowski, Rainer Schulze, Tamas Stark and Barbara Stelzl-Marx, 2008) and "Death at the Berlin Wall" (2010).