A couple of series books this time and a classic.
I'm catching up to the present in my Dalziel/Pascoe reading; Beyond the Wood was written just over a decade ago. But its heart is set in WWI, specifically at Passchendaele, where British forces fell in huge numbers to conquer a very small area of land. Pascoe finds out that one of his grandfathers was court-martialled and executed for cowardice in the battle, and he investigates further. The WWI story doesn't really impinge on the modern story, which I actually thought was a good thing; very often mystery authors try to tie two crimes together -- one from the distant past and one in the present -- and it's pretty unconvincing.
The other notable event in this book was that Dalziel falls for a suspect again. It's reminiscent of An April Shroud, the fourth book in the series (and Hill even has one of the characters mention the earlier case), but Hill handles it more maturely and subtly this time around. On the one hand, it's not fun to see an author turn to recycling earlier plot ideas, but in cases like this, where he returns to a theme that he wasn't as adroit at earlier, I think it's nice to see the improvement.
The theme of Cabal is illusion and reality and their interaction. The book centers around a mysterious conspiracy within the Knights of Malta that conducts assassinations and controls finances. The punch line, of course, is that the conspiracy doesn't exist, but, even so, there are concrete results from the belief that they exist. Crimes are committed to get more information about them, Aurelio's life is placed in jeopardy because others think he knows about them, and so on. This theme carries through into the subplots as well -- there's a humorous side story about Aurelio and his girlfriend each suspecting the other of infidelity because they've created an illusion around the work they do, hiding the details from the other.
We also have Zen trying to actively be a corrupt cop, trying to take a bribe from a suspect to drop the case, and failing miserably by shooting the suspect instead. In the end, fate seems to destine Aurelio for the side of the angels, even against his own wishes.