Night Watch - (Discworld Novel 29)

'DON'T PUT YOUR TRUST IN REVOLUTIONS. THEY ALWAYS COME ROUND AGAIN. THAT'S WHY THEY'RE CALLED REVOLUTIONS. PEOPLE DIE, AND NOTHING CHANGES.'The twenty-fifth of May is an important, sombre day in Ankh-Morpork - the anniversary of one of the city's bloodiest rebellions. But crime stops for nothing, as Commander Sam Vimes of the City Watch knows. When a notorious serial killer emerges from hiding, the chase leads the Watch to the roofs of Unseen University where a magical storm is brewing.
It's a case of wrong place, very wrong time. For Vimes finds himself back in his own rough, tough past with only a killer for company and a city on the brink of revolution to contend with. But he must survive, because he has a job to do: track down the murderer and change the outcome of the rebellion. And get back to the future before his wife gives birth, of course. All in a day's work ...'The best Discworld book in the whole world ever.
Until next time.' SFXNight Watch is the sixth book in the City Watch series, but you can read the Discworld novels in any order.