Both excellent.
The Truth focuses around Ankh Morpork and Pratchett's vision of industrialising the disc. This is the development of the Newspaper in the form of the Times, run by William de Worde, which focuses on the news itself and getting the truth to the masses.
It also shows us some of hsi rivals, the unscrupulous tabloids, who make up their stories to sell a paper.
Good, but not as good as Thief of Time
This book brings us back to our friend, the sweeper aka Lu Tze. As you shoul know, he is a history monk and he has to help time come full circle, by encouraging her child to take up her position, because she is going to die. (It is how it work)
Thief of time comes complete with a full supporting cast of heroes, vilains,yetis, martial artists and Ronnie, the fifth horseman of the apocalypse (Who left before they became famous).