The Columbia University educated historian embarked on his mystery writing career in 1988, six years before he retired from the WIU history department. O'Brien's wife Elvy, an art historian, had moved to Williamstown, VA, after accepting a position with the J. Paul Getty Trust, then at the Clark Art Institute. That began a series of long commutes for O'Brien.
"I wanted to make use of time on board (trains and planes) and in airports. Many of my fellow passengers were reading crime novels. I thought why not exploit my fund of historical settings and write a historical mystery," O'Brien explained. "The idea of 'Mute Witness' blossomed in the air between Albany and Chicago."
When O'Brien retired in 1994 after 22 years of teaching at Western, he began to seriously study the art of writing fiction with colleague Tama Baldwin of the WIU English faculty.