Social historians of the future may look back at the reading habits of this era and conclude that we were almost exclusively interested in Nazis and Nordics. Certainly there seems no diminution in these twin tastes. Widowland (Quercus, £14.99) by C.J. Carey (a pseudonym for the writer Jane Thynne) is the latest Nazi-related novel in a crowded field, and its author wisely opts for a different, if not altogether original, conceit.