POLLY Perks found cutting off her hair and wearing trousers was easy. Learning to break wind in public and walk like an ape took longer.

Having mastered these arts, however, she was ready to become Oliver Perks, a young lad searching for her older brother.

Add to the plot a troll, an Igor (very handy with a needle and body parts), a vampire (who's sworn off blood but drinks lots of coffee), a bullying corporal, a sergeant who is known by everybody everywhere, a recruiting drive, and a few village lads, and you have the Monstrous Regiment, the last recruits to a desperate war.

They are fighting for a duchess who hasn't been seen for decades, a country at war with all of its neighbours at once, and a god described as being like "the kind of people who write letters to (the Ankh-Morpork Times) letter column."

Vimes and the Watch have been sent along to sort things out, although they only have a minor role in this book, the star being Cpl. Perks, with an excellent supporting cast.

The book is full of Pratchett's detailed observations strung out with asides and a liberal dosing of humour and occasional gore, as people (in the loosest sense of the word) turn out to be not who, or what, you were expecting.

Monstrous Regiment is one of Pratchett's best Discworld novels so far, a Hallowe'en treat that in places will make you howl with laughter, but will mainly make you think, as you head towards what you know will be the right, if not the happiest, ending.

Updated: 08:55 Wednesday, October 29, 2003