The Wee Free Men

There's trouble on the Aching farm - a monster in the river, a headless horseman in the driveway and nightmares spreading down from the hills. And now Tiffany Aching's little brother has been stolen by the Queen of the Fairies (although Tiffany doesn't think this is entirely a bad thing).
Tiffany's got to get him back. To help her, she has a weapon (a frying pan), her granny's magic book (well, Diseases of the Sheep, actually) and -
'Crivens! Whut aboot us, ye daftie!'
oh, yes. She's also got the Nac Mac Feegle, the Wee Free Men, the fightin', thievin', tiny blue-skinned pictsies who were thrown out of Fairyland for being Drunk and Disorderly . . .
A wise, witty and wonderfully inventive adventure set in the Discworld(c).