It would be a very long bookshelf indeed that would accommodate all the books with the name Waugh on the spine. Teresa Waugh, widow of the late and much-lamented Auberon, although not a blood relation, has successfully adopted the family business and would take up a respectable amount of space on that bookshelf herself. A Long Hot Unholy Summer is her ninth novel. It is set in a part of France which Waugh obviously knows well, and tells of a family whose house in France has always been their ideal summer retreat. But not this summer. Isabelle, the 15-year-old daughter of the house, is abducted by a man to whom she has been talking online and whom she has agreed to meet for the first time. Her distraught parents, to whom she has lied about where she was going that day, with their house ful