He had not moved his skis as he turned, and when he started again he kept on in the same straight line, and he also kept on counting. His paces on the skis were just about a metre, so after a thousand he had done a kilometre; the air black; the blackness now all roaring. [loc.5755]
Johnny Porter is a Gitxsan Indian, a professor of anthropology with a knack for languages and the ability to adopt a plethora of identities: as a Korean seaman he infiltrates an isolated research base in the dark and frozen waste of Siberia, and as a Lapp trucker he carries out the mission requested of him -- in code, naturally -- by a former acquaintance. It is all highly dangerous and thrilling stuff, and yet curiously disappointing. There's far too much about car mechanics: far too little about the landscape, the astonishing scientific / archaeological discovery at the heart of the story, or Porter's inner life (if indeed he has one).
I found polymath Porter an improbable protagonist -- he has no discernible flaws (or indeed personality) and I find his irresistability to women (a) sordid and (b) inexplicable. (Does he have to sleep with every female he encounters? Ludmilla excepted ...) He endures hardships which would distract anyone from their quest -- with little apparent motivation. The plot is full of reversals and twists -- Philip Pullman's introduction lauds its classic quest structure and the intelligence of the storytelling -- but somehow manages to plod. Perhaps it's Porter's imperturbability that flattens the affect. Even fleeing for his life across Siberia in winter, Davidson only mentions his 'anxiety'.
Coincidentally, a couple of days after finishing the book I found this photoessay about Siberian truck routes: On Thin Ice: Guardian, 11 May. It illustrates the landscape of the novel very well.