Like a good French wine, the Bruno series is improving with age.
Black Diamond is more complex than the first two titles, and encompasses a wider geographical area, but does not suffer for it. Rather, the author seems more confident in his characters, his plot, and his ability to tell a ripping good yarn.
The only thing that stopped me from finishing Black Diamond in a single sitting was the occasional trips to poke around the kitchen when the descriptions of sumptuous food got too much for me to cope with without a snack.
For a perfect summer read that encompasses a bit of something grisly, minor warfare, romance, la France profonde, and small village life, you could do no better.