After an excursion to Argentina, the chief exponent of minimalist melancholy has returned to his own ground. Colm Tóibín’s third novel, The Story of the Night, was set in Galtieri country, in the terrain of the disappeared and the shadowy. It was an enigmatic work, which left a vapour-trail of apprehension in the reader’s mind. The Blackwater Lightship begins solidly in a Dublin suburb, where two married schoolteachers are starting their summer holidays. But the story soon moves to the coastal south-east, where land must negotiate for survival with the wind and the sea, and individuals must protect themselves from the eroding claims of family and the past.