By Errol Morris
Mr. Morris is the director of a 2013 film about Donald Rumsfeld, “The Unknown Known.”

Trying to understand another human being is often a dismal task. And if not dismal, thankless. What am I supposed to do? Disapprove of Donald Rumsfeld? That’s easy. Perhaps too easy. He was ambitious, driven — also lucky. And, as we all know, he was one of the chief architects of the disastrous war in Iraq.

It is impossible for me to write about Mr. Rumsfeld, the former U.S. secretary of defense who died on Tuesday, without writing about his memos.... Read more about "New York Times" Opinion Guest Essay: "Donald Rumsfeld's Fog of Memos" by Errol Morris