Thud!

"Long, long ago, in a gods-forsaken hellhole called Koom Valley, trolls and dwarfs met in bloody combat. Centuries later, each side still views the other with simmering animosity that has been heightened of late because of one Grag Hamcrusher. The influential dwarf has been fomenting unrest among a section of Ankh-Morpork's citizenry-a volatile situation made far worse when the petite provocateur is discovered bashed to death . . . with a troll club lying conveniently nearby. If he doesn't solve the murder of just one dwarf, Commander Sam Vimes of Ankh-Morpork City Watch is going to see it fought again, right outside his office. But more than one corpse is waiting for Vimes in the eerie, summoning darkness of a labyrinthine mine network being secretly excavated beneath Ankh-Morpork's streets. With war-drums beating ever louder, Vimes must unravel every clue, outwit every assassin, and brave any darkness to find the solution. And the darkness is following him, pulling him deep into the muck and mire of superstition, hatred, and fear-and perhaps all the way to Koom Valley itself. Until six o'clock every day, when without fail, the Commander goes home to read Where's My Cow?, with accompanying farmyard noises, to his little boy. Because there are some things you must do. The Discworld novels can be read in any order but Thud! is the 7th book in the City Watch collection and the 34th Discworld book"--