Colm Tóibín's mothers don't always behave as they should; they are often unpredictable, occasionally downright troublesome, prone to gusts of passion or rage or – worse – unnatural indifference. Rarely are they uncomplicated figures of placid, nurturing devotion; but they do make for fantastically involving fiction. In his 2006 short-story collection, Mothers and Sons, Tóibín brought us relationships that were often characterised by the way they inverted traditional roles. An entrepreneurial widow plots to escape to the anonymity of the big city, clashing with her son's determination to hold fast to their small-town life; another man slinks away from a crowded pub rather than be spotted by the celebrated mother who has absented herself from his life; in "A Long Winter", a magnificent extended piece set in rural Spain, a young man is forced to keep house ineptly for his father after his alcoholic mother walks out into a snowstorm rather than be deprived of drink.....