A Cumbrian wind is the central character in this hugely ambitious, millennia-spanning novel, which was 20 years in the makingEven if Sarah Hall did not begin her acknowledgments by saying that it’s taken her 20 years to write Helm it would be evident. Not from a cursory glance at her bibliography, perhaps: in that time Hall has published six other novels and three volumes of extraordinary short stories. But in every other way, and the moment you begin reading.There’s the subject, for starters. Ever since the first paragraph of her first novel, Haweswater, in which an early 20th-century man drives his horse and cart through the waters of a Cumbrian valley recently drowned by a dam, Hall has been concerned with landscape, with weather, with nature in all its forms, with the ways in which we affect each other. In The Carhullan Army, climate change has already happened. Cumbria is semi-tropical, temperate England a folk memory; a dystopian vision that feels, this baked summer, uncomfort...