Once again, Ankh-Morpork is on the verge of chaos, and once again, it's all watch commander Sam Vimes can do to keep control of the situation.

Vimes has come a long way from the man he used to be when he was first introduced in Guards! Guards! Guards! One of the Discworld's most richly textured characters finds himself in the middle of a richly textured plot that also, and vey happily, makes the best satirical fun of The Da Vinci Code I have yet read. (And if any book deserves to be made fun of....) Pratchett's books are either thoughtful or laugh-out-loud funny. Thud! happens to be both.

The anniversary of the Battle of Koom, the ancient conflict between Dwarves and Trolls -- and the only known war in which both sides managed to ambush one another -- is fast approaching. Although they have lived under a truce for years, the ethnic tensions between the Trolls and the Dwarves is starting to boil to an unhealthy level. A bunch of fundamentalist Trolls, preaching the old ways, have arrived in town and are causing mischief by stirring up the old enmity. A rabble-rousing Dwarf is murdered, the Trolls are blamed and blood threatens to run in the streets of Ankh Morpork. Again.

Pratchett -- whose books have evolved from sword-and-sorcery satire to much heavier issues such as ethnic bias, racial tensions, law and order, conspiracy theories, war, justice and everything else human beings get up to -- gets right into it again. Thud! begins with a murder-mystery and ends with the Nightwatch crew desperately trying to prevent a war between two groups who are looking for any excuse to wipe each other out. Of course, it's not just a plain old war. Naturally, and as usual, there's a dark and sinister force at work behind the scenes that wants to use the escalating tensions for its own advantage: namely, to be free to be in the world once more in order to create even more chaos. Vimes is on a journey to discover the truth, stop the racial war that's building to frightening levels and, no matter what, be home by 6 p.m. to read Sam Jr.'s favorite book to him. (It's called Where's My Cow?, and yes, it's an actual children's book by Pratchett, written after he published Thud!)

Thud! skewers the aforementioned Da Vinci Code, as well as The Lord of the Rings, police detective novels and Illuminati-style conspiracy theorists, all in the dry, scathing Britwit we have come to know, love and expect from Pratchett. His ongoing theme this time is prejudice and how it flourishes in urban environments. His proxies are werewolves, vampires, et al, but of course he's holding all our current religious and political circumstances up to the light and wondering just where it's all gotten us, if anywhere at all. But never once, in all his clever, humorous, multi-layered stories have I ever felt Pratchett giving up on humanity, nor have I ever picked up even a hint of the author assuming the role of the angry, obstreperous parent that so many writers afflicted with pessimism seem to assume. (Are you listening, Frank Miller?) Oh, he neatly takes us all to task a bit, but he's not really giving up on us.

That said, I felt at times, as I have felt with so many of his recent novels, that Pratchett is getting to be a bit of a romantic. The polygon plot works well enough and the characterization, for the most part, manages to remain both dead-on and dynamic at the same time. But time changes everyone. Pratchett's books no longer have the crisp, snappy feel of a true "send-up," or at least not the whole way through. The endings are becoming sweeter and sweeter, more like holding hands and let's all try to get along, and a bit less realistic. Perhaps it's the conservative in me, but I don't always believe that life, even in a fantasy novel, can be smoothed over so quickly; otherwise, there wouldn't be problems in the first place, would there?

As well crafted as his plots can be, and they are normally sharp as well-cut jewels, there are times when it's a little bit difficult to sort out what's actually going on when the rollercoaster endings are in motion. This effect is created partly by trying to take on too much themewise, and partly by Pratchett's attempts to turn his endings into unifying lessons. It's not just a murder-mystery, it's also a Dark and Sinister Force in the Universe fantasy epic, which also happens to be tackling the subject of racism, not to mention the love story he touches on briefly. Mixing goofy fun, which Pratchett is famous for, with a more serious message, requires a very delicate touch. While I don't mind emotionally charged stories and Higher Meanings combined with comedy, endings that are too touchy-feely can end up negating the rather fine chaos he delineates in his stories-with-a-message. Being too multi-faceted weighs down the neatly constructed plot with too many expectations, which tends to cut off the oxygen flow; there's probably enough here for a trilogy.

I also felt that there were a couple of fascinating new characters that are introduced in Thud! who did not get quite enough time to be properly developed, specifically Sally the vampire, the newest addition to the Nightwatch. There was no real exploration of her as a character, which is unfortunate given her budding dispute with Corporal Angua, who happens to be a werewolf, over the affections of Watch Captain Carrot Ironfoundersson.

Still, there's enough fun in there to keep even someone who isn't a fan busy. In dealing with Pratchett's later works, I've found it's best to just turn off analysis and go with the flow. Thud! is incredibly witty, loads of fun with a dry pun on virtually every page and hands down the best escapist reading to come out of Britain since, well, the last Terry Pratchett novel was released. No one has his imagination, his unique comedic flair, his incredibly huge cast of characters, his world-building abilities or his grandly orchestrated plots, at least not all in one book. If you like it wry and dry, then get your hands on a copy of Thud! and enjoy.