Lawrence Birken, history professor, died Sunday afternoon due to hemorrhaging of the brain, history department Chairman Daniel Goffman said.
Goffman said doctors discovered the brain hemorrhage 10 weeks ago when Birken, 51, checked himself into the hospital.
Though he underwent surgery, he was never able to return to work, Goffman said.
His death was unexpected because he had been improving until Saturday afternoon, Kevin Smith, assistant chairman, said.
Arrangements for services had not been announced at press time.
Birken's colleagues remember him for his dedication to history.
"Larry was always willing to be of assistance," Smith said. "He never hesitated to take on more responsibilities if I needed him to."
Smith said that Birken was a brilliant man and a personable colleague.
Chris Thompson, associate professor, said he was a "rare combination."
"Wildly published and a prolific scholar in a variety of historical fields, Professor Birken was also a committed teacher who continually challenged his students and himself to think about history in new ways," Thompson said.
Ashley Braucher, freshman, said she enjoyed having him for History 150.
"I thought he was a good teacher, and he really cared about students," Braucher said.
Though dedicated to his work, he was fun and laid back, Anthony Edmonds, professor, said.
"His idea of well dressed was remembering to get dressed," Edmonds said. "He didn't have a pretentious bone in his body."
Thompson said he enjoyed his humor.
"He was such a character," Thompson said. "What I'll miss most was his readiness to laugh."
Thompson said most people recognize him because he rode his bicycle everywhere.
His hemorrhage might have been caused by a bicycle accident he had a few days before he went to the hospital, Edmonds said.
Birken taught German history, History 150, intellectual history and Honors colloquia.
Birken's classes have been taught by other history professors since his surgery.
"The thing that impressed me the most... was his enthusiasm," Edmonds said.
Edmonds hired Birken in 1989, he said.
"Every research project he took up was something you wouldn't expect," Goffman said.
Goffman said the most interesting project Birken undertook was his book, "Hitler as Philosophe: Remnants of the Enlightenment in National Socialism," which compared Nazism to French philosophers of the 18th century.
Birken wrote three books and several scholarly articles.
Birken graduated from the University of Michigan and earned his doctoral degree from Rutgers University.