The City Watch Trilogy

Be a MAN in the City Watch! The City Watch needs MEN! (or dwarves or trolls or gargoyles or ¿)
The City Watch is a bumper volume in which those noble defenders of Ankh-Morpork, the greatest city of the Discworld*, come face to face with some of the most heinous crimes in history.
GUARDS! GUARDS! Sees some night-time prowler turning (mostly) honest citizens into something resembling small charcoal biscuits.
In MEN AT ARMS, there¿s a murder to be solves so that the world-weary Captain Vimes can be married at noon and retire happily ever after.
And in the Discworld Howdunnit FEET OF CLAY, someone is murdering harmless old men and poisoning the Patrician ¿and the golems are committing suicide ¿

*Which is flat and rides through space on the back of four elephants who stand on the shell of an enormous turtle, as everyone knows.