William W. Hagen (born 1942) is a prominent historian and Professor of History at the University of California-Davis. Hagen's focus is on Modern European History, primarily in relation to Germany and Eastern Europe. He obtained his B.A. from Harvard University and his M.A. and Ph.D. from the University of Chicago. Starting as Assistant Professor in 1970, [1] he became Associate Professor of History in 1977 and Professor of History in 1981. From 1992-1998, Hagen served as Director of the UC Davis Center for History, Society, and Culture. In 1996, he served as President of the Conference Group for Central European History (American Historical Association).