Feet of Clay by Terry Pratchett (1996)
Commander Sir Sam Vimes has a problem. His wife Sybil insists that he go to the Ankh-Morpork Royal College of Heralds and get himself a coat of arms drawn up. Oh, and two people have been found murdered with the only clue a small lump of white clay found at the scene of each crime and someone is trying to poison Lord Vetenari. The Assassins Guild denies any involvement, so there is a freelance killer loose in the city.
It's a toss up which he thinks is worse.
I have a particular fondness for the Commander Vimes stories. Because they tend to be mysteries, almost whodunnits and thrillers in some cases, they are much more tightly plotted than Pratchett's other Discworld novels and I've always found Commander Vimes a real treat of a character. As the dedicated beat cop promoted to suit his abilities, but way above his preferences, He's a marvellous combination of weariness, frustration, anger, stubbornness, anger, suspicion, anger, resourcefulness, anger and anger. He's also a wonderfully stable centre for the Watch, a police force that includes trolls, dwarves of both (albeit indistinguishable sexes), werewolves, humans and Corporal Nobby Nobbs, who has a letter that states that, appearances to the contrary, he's human, too.
Feet of Clay twists with all manner of subplots that eventually tie up nicely and the climax highlighted by Pratchetts comic imagination and talent for a neat turn of phrase. Only Pratchett could come up with a rat catcher who meets his quarry face to face (well, forehead to forehead) and can make proper characters out of walking lumps of clay.
The only sad part about Feet of Clay is that it shows how the world has changed since he wrote it back in 1996. Then, his satirical city of Ankh Morpork was a wonderfully twisted version of a modern Britain trying to cope with immigrants. There may have been dwarfs, vampires, zombies, gnomes and golems moving into the city, but they were all hard working and, aside from the odd riot, wanting to get on with their lives. Unfortunately, in a modern Britain where immigration has become colonisation and includes a sizeable faction of fanatics who despise their host country and actively work to overthrow it, that happy image seems as hard to see in our world as one that rests on the back of a giant turtle.