In 2013 Ian Crofton undertook a journey he had been pondering for years: a walk along the Border between Scotland and England. It would be an exploration both of his own identity - not quite Scottish, not quite English - and of a largely unexplored stretch of country. Apart from the line marked on the map, the route is not obvious. For much of its length the Border either follows the middle of various rivers, or traces the Southern Upland watershed,...