One September morning in 2008 an investment banker approaching forty his career in collapse & his marriage unravelling receives a surprise visitor at his West London home He struggles to place the dishevelled figure carrying a backpack until he recognizes a friend from his student days a brilliant man who disappeared years earlier under mysterious circumstances The friend has resurfaced to make a confession of unsettling power Theirs is the age-old story of the bond between two men & the betrayal of one by the other As the friends begin to talk & as their room becomes a world a journey begins that is by turns exhilarating shocking intimate & strange Set against the breaking of nations & beneath the clouds of economic crisis & moving between Kabul New York Oxford London & Islamabad In the Light of What We Know tells the story of people wrestling with unshakeable legacies of class & culture & pushes at the great questions of love origins science faith & war In an extraordinary feat of imagination Zia Haider Rahman has woven the seismic upheavals of our young century into a novel of rare compassion scope & courage