A Discworld novel.
First a priest is murdered, and found with a slip of paper in his mouth. Then a curator. And Vimes has no idea how this is happening, or why anyone would kill a couple of harmless old men. To make things worse, he learns that the extremely un-royal Corporal Nobby Nobbs may be the rightful king of Ankh-Morpork (if that doesn't warp your view of reality, nothing will), and that the Patrician is being slowly poisoned -- but no one knows just how the poison is being administered.
The answer to the mysteries may lie in the golems: Not-living-but-not-dead creatures made out of clay, who don't speak and always follow orders. Theoretically they can't kill . But they come under suspicion when, inexplicably, they start destroying themselves as the evidence starts to point toward a golem murderer. However, Vimes soon learns that the conspiracy is far more extensive -- and sinister -- than the golems...
"Feet of Clay" is not merely a murder mystery (although it has one of the coolest ways of murdering a person that I've ever heard of). Pratchett also offers some commentary on society, on what makes a person a person. His handling of the golems is remarkably thought-provoking. And their connection to the attempted murder is also very hard to unravel -- you won't guess who or how or why.
This is, in some ways, more serious at times than his other books; one scene has Vimes exploding over the death of a little child and a cleaning lady. But don't think he's abandond his skewed brand of Discworld humor: the rebelling dwarf, the unsuccessful assassination at the beginning, Nobby's outrageous behavior and seven grandmothes, and especially a vampire with self-destructive tendencies (sunglasses tester, garlic stacker, pencil factory worker, holy water supplier). Not to mention the organizer with the little imp inside.
As always, Vimes is the hard-boiled scrap of sanity among the weirder characters. Angua is, unfortunately, much flatter than the weirder characters; Carrot is his usual likable self, while Nobby gets to act more bizarrely than usual as he is accepted into the upper crust as an aristocrat (a thieving, unsanitary one). Detritus is a likable clod, and we get a new character in Cheery Littlebottom, a dwarf female who wants to start looking like one. And Pratchett outdoes himself with Dorfl, a secretive golem who never speaks or changes expression.
While not Pratchett's best, "Feet of Clay" is a solid mystery/fantasy/commentary with plenty of humor and suspense. Definitely worth looking at.