Eiber studied History at the University of Munich and received his doctorate there in 1978 with his dissertation on the experience of slave workers under the Nazi regime.
In particular, he focused on the experience of textile and porcelain workers in the northeastern Upper Franconia, 1933–1939.
[1] He then did research until 1991 at the Hamburg Foundation for Social History of the 20th century, on the Hamburg workers' resistance (1933-1939) and in connection to Leibniz University Hannover and the emigration of Social Democrats to Great Britain (1940-1945).
From 1996 he was a research associate at the House of Bavarian History and completed his Habilitation in 1997 at the University of Hamburg: Arbeiter und Arbeiterbewegung in der Hansestadt Hamburg in den Jahren 1929–1939: Werftarbeiter, Hafenarbeiter und Seeleute; Konformität, Opposition, Widerstand.
From 1998 to 2003 he was project leader in the revision of the exhibition at the Dachau Concentration Camp.