A Pulitzer Prize-winning historian and author, he is best known for his work on post-Civil War Reconstruction. He published his award-winning work, The Fiery Trial:
He graduated summa cum laude from Columbia University in 1963.
He was elected president of the American Historical Association in 2000.
His father was a historian who was blacklisted during the McCarthy Era for supporting civil rights and the trade union movement.
He frequently wrote about Abraham Lincoln's views on slavery.