Gerd Langguth ( 18 May 1946 -- 12 May 2013 ) was a professor of political science at the University of Bonn and the author of biographies of Angela Merkel and Horst Köhler .
Gerd Langguth ( 18 May 1946 -- 12 May 2013 in Cologne ) was a German professor of political science at the University of Bonn and the author of biographies of Angela Merkel and Horst Köhler .