Richard Hannay is tasked to investigate rumours of an uprising in the Muslim world and takes off on a hair-raising journey through German-occupied Europe to meet up with his old friend Sandy Arbuthnot in Constantinople, where they must thwart the Germans' plans to use religion to help them win the war. In <I>Greenmantle</I> John Buchan clearly asserts his mastery of the genre of the espionage thriller, by drawing on his wide first-hand knowledge of the worlds of politics and secret intelligence. Set during World War I, <I>Greenmantle</I> is a powerful meditation on the power of political Islam.