The Oath tells the story of two brothers-in-law whose experiences take us into the heart of Al Qaeda territory and on to Guantanamo Bay. Abu Jandal, once one of Osama bin Laden’s closest bodyguards, now makes his living driving a taxi in Yemen. Meanwhile, the brother-in-law he recruited to Al Qaeda and who subsequently became Bin Laden’s personal driver, Salim Hamdan, sits in a cell in Guantanamo under seemingly tenuous charges of terrorism. The film is not only a rich psychological study of Abu Jandal, who expounds expansively on his views—religious and political—over the course of two years, but also a sensitive portrait in absentia of Hamdan, whom we never meet but whose letters reveal the emotional toll being in Guantanamo takes. The second feature in filmmaker Laura Poitras’s trilogy about our post-9/11 world, The Oath, though at times unsettling, is a vital window into a part of the world too few attempt to understand.  ST