Peter Lovesey has two strong elements going for him with this mystery series: the rich history of Bath and the engaging character of Peter Diamond, his detective superintendent, head of the Bath murder squad.
Peter Diamond is a big man - overweight, unfit, funny and irascible by turns, and totally consumed by his job. A demanding boss, he assumes everybody wants to work as hard as he does. Oddly enough for a man who's often in a rush, he likes to drive slow (even old ladies pass him). He's put off by technology but not above using it. In this book he's painfully learning to use his cell phone.
The focus of the action is Lansdown, a hill near Bath where the Roundheads fought the Cavaliers in 1643. The locals periodically re-enact the battle in historic costumes for enthusiastic audiences. During the latest re-enactment, two Cavaliers sneak off to have a few beers under an ancient fallen oak. Some cans are missing, and digging around in search of them, the men find a human femur. Finally they re-bury it out of respect, assuming it's a combatant killed centuries ago.
But in fact the skeleton is no more than 20 years old - and headless. That gets the police to wondering. And when one of the Cavaliers who found the skeleton is murdered, Peter Diamond suspects that the two deaths must be linked.
There are lots of eccentric characters in the story, and interesting glimpses of the sex trade and the aristocratic horseracing scene. The mystery is solved by putting a hundred bits and pieces of information together from interviews, research, forensics and plain old-fashioned snooping. It's quite absorbing to go through the process with Diamond and his team.
I highly recommend the whole series, as well as this latest book.