'Herzog's existential journey through a hostile winter landscape is one of the great modern pilgrimages - a record of physical suffering, of hallucination and ecstatic revelation, of portents and animals, of the wreckage of history and myth. Of Walking in Ice has the eerie power of the best fairytales. It hits you with the force of dreams and leaves you with the taste of snow-filled air' Helen MacDonald, author H is for Hawk, winner of the 2014 Samuel Johnson Prize for non-fiction