Educated, University Bonn. Educated, Ohio University. Doctor of Philosophy, University Cologne, Germany, 1960.
Assistant professor German history, Colgne, Germany, 1968—1970. Assistant professor American history John F. Kennedy Institute Free University, Berlin, 1970—1971. Professional, chairman Department History University Bielefeld, Germany, 1971—1996, professor emeritus Germany, since 1996.
Visiting professor Harvard University, Massachusetts, 1972, Massachusetts, 89, Princeton University, New Jersey, 1976, Stanford University, California, 1983—1984, California, 2004, University Bern, 1987—1988, Yale University, Connecticut, 1997.
Member of American History Association (honorary. Foreign member), American Academy Arts and Sciences (honorary.
Married Renate Pfitsch, 1958. Children: Markus, Fabian, Dominik.