Master documentary filmmaker Errol Morris is back with his latest buzzed-about doc, "The Unknown Known," which opens April 2. RADiUS-TWC today released the trailer for the film, which finds Morris interviewing former U.S. Secretary of Defense Donald Rumsfeld, one of the most polarizing figures in American politics. 

In his review out of the Telluride Film Festival, Indiewire's Eric Kohn wrote:

Over the course of 106 minutes, Rumsfeld's rambling assertions grow exhausting, particularly because Morris never manages to direct them toward a larger argument. Unlike "The Fog of War," where Vietnam architect Robert McNamara had some 30 years to contemplate his misdeed and reflect on them with a protracted philosophical perspective, Rumsfeld seems as though he's still living through his delusions and never manages much in the way of self-analysis.

Go here for full review and watch trailer below.