There is something irresistible about Joshua Lawrence Chamberlain, the soft-spoken, be-spectacled Bowdoin College professor who somehow transformed himself into one of the Union Army’s ablest commanders. He was one of the protagonists in Michael Shaara’s vivid novel about Gettysburg, The Killer Angels, and the real hero of John J. Pullen’s fine history of Chamberlain’s regiment, The Twentieth Maine, and when Ken and Ric Burns and I were working on the script for the PBS series The Civil War, he was among the soldiers whose exploits we followed most eagerly.