Black Diamond is the 3rd Bruno Courrèges, Chief of Police novel by Martin Walker. It has all of the familiar atmosphere of the first 2 novels but takes a few darker turns in the plot-line by the end. I am thoroughly enjoying reading the Bruno series and was lucky enough to discover them late so that I can read all 4 (to date) of them this summer of 2012.
What keeps these novels from hitting 5 out of 5 territory for me is that the plot resolutions are always summed up far too quickly in the final 1 or 2 chapters. Everything is explained but it is not quite enough for this reader's satisfaction. Everything that comes before is quite solid, terrific trivia about French food and wine (in this case, the "Black Diamonds" of the title are the black truffles that grow in the Périgord region of Southwestern France) and Bruno's fellow inhabitants of the fictional village of St. Denis.
The plot this time kicks off with Bruno investigating a suspected fraud in a neighbouring village truffle market. Then a subplot of conflicts between Viet and Chinese immigrant communities in France is introduced that further leads to the murder of one of Bruno's friends. The friend turns out to have been one of the "barbouzes" (the bearded ones), a former member of French intelligence services active in the French colonial conflicts in Vietnam and Algeria. Meanwhile, a pending mayoral election in St. Denis introduces 2 opposing candidates to Bruno's mentor and father-figure Mayor character. There is also the regular ongoing plot of Bruno's love relationships. These are all resolved by the end, but perhaps just a little too quickly.