Number of pages: 283
This is the first Discworld book since Eric to revolve around the hapless wizard, Rincewind. This time he is sent to an empire where rebellion is breaking out because apparently he is thought to be "the great wizard".
Right from the start, it is fairly clear that this is a bad idea, and Rincewind spends a lot of the book running away, while a band of elderly warriors led by Cohen the Barbarian storms the city, and it is fairly clear that a war will break out soon.
Most of the humour in the book comes not only from "the horde" being taught to be polite as they pillage the city and attempt to overthrow its emperor, but the fact that everyone puts their trust in Rincewind, despite the fact that even he knows he is hopeless. He actually manages some quite impressive things in this book, but they all come across as the result of dumb luck.
[Spoilers behind the cut]Also, this book is notable for the fact that Twoflower, who was a main character in the first two Discworld titles, makes a return appearance in this book, although he doesn't show up until about half way through the book; this gives Terry Pratchett an opportunity to return to the brilliantly-written relationship between the two characters that proved to be very entertaining before. Also, after Rincewind has helped win the war by pure fluke, the story ends in a cliffhanger that sets up the subsequent book, The Lost Continent (Discworld #22).
Overall, having another Rincewind story after seven novels without him is a welcome return to one of the most popular characters from the series, and this book is just as funny as the previous ones.
Next book: To Make a Killing (Michael Crawshaw)