[4][5] In August 1964, he married Brenda Jean Pursel, founder and artistic director of the Touring Theatre of North Carolina.
His interpretation of the Final Solution as a product of unplanned evolution rather than premeditated 'grand design' triggered a debate that has energized Holocaust scholarship over the past two decades.
– Christopher Browning, author of The Final Solution and the German Foreign Office[7]In the 1960s, along with a handful of European and American scholars, Karl helped establish a new field in modern historical studies.
His ground-breaking research in the Berlin Document Center which holds materials captured from the Germans, provided him with evidence to produce an exhaustive analysis of the policies which led to the murders of six million Jews.
Karl will be remembered for his many years of workshops sponsored by the NC Council on the Holocaust Teacher Workshops[8] teachers across the state and as the honoree of the Schleunes Lectures which annually bring a well-known Holocaust scholar to speak at Greensboro College, an event sponsored by Richard and Jane Levy.