Former defense secretaries are making news in recent days, with the release of Robert Gates’ Duty: Memoirs of a Secretary at War and now with the upcoming release of the Errol Morris directed documentary, The Unknown Known. The Unknown Known offers a portrait of the polarizing Donald Rumsfeld, who served two stints as secretary of defense under Presidents Gerald R. Ford and George W. Bush. The title of The Unknown Known comes from a famous quote given by Rumsfeld to a news briefing on Feb. 12, 2002. In response to a question about the absence of weapons of mass destruction in Iraq, Rumsfeld answered, “… there are known knowns; there are things we know that we know. There are known unknowns; that is to say, there are things that we now know we don’t know. But there are also unknown unknowns – there are things we do not know we don’t know.” Rumsfeld himself used part of that quote as the basis of the title of his 2011 book, Known and Unknown: A Memoir. Morris has carved somewhat of a niche for himself in making documentaries about former defense secretaries. He won an Academy Award in 2003 for The Fog of War, another documentary about a polarizing secretary of defense, in that case Robert McNamara. The Unknown Known will be in theaters on April 2.