In Errol Morris' Oscar-winning film, The Fog of War, former Defense Secretary Robert McNamara was conscience-stricken over the war in Vietnam. Former Defense Secretary Donald Rumsfeld told Morris he hated it, because "that man had nothing to apologize for." Then Rumsfeld sat down for an interview of his own — without demanding any right of approval. The result is The Unknown Known, which addresses what Morris calls the "contradictions and falsehoods" associated with decisions to go to war.