My favourite Discworld novel (and I've read them all!).

The underlying frame of the novel is a disertation on the power and influence of narrative, of how certain plotlines are memes which permeate human society. Thus any poor and downtrodden but beautiful stepdaughter will end up marrying a prince, little girls travelling to Granny's house through the forest will always meet talking wolves, housekeepers will always be fat and bustling and wizened old toymakers will always be merry and whistle while they work. Oh, and witches will have houses dropped on their heads. Thank God for reinforced lining.

By continually and irreverently taking the piss out of dozens of folk tales, popular fairy tales and children's books, Pratchett reflects back to us the way in which we rely on these memes to guide us through life and contort reality in order for it to fit into familiar patterns. In the grand finale we are presented with a demostration of how monstrously difficult it is to cling to reality in the face of convenient illusions.

Incredibly funny and very thought provoking. Highly recommended.