WHAT WE CAN KNOW, Ian McEwan2014: A great poem is read aloud and never heard again. For generations, people speculate about its message, but no copy has yet been found. 2119: The lowlands of the UK have been submerged by rising seas. Those who survive are haunted by the richness of the world that has been lost. Tom Metcalfe, an academic at the University of the South Downs, part of Britains remaining island archipelagos, pores over the archives of that distant era, captivated by