It helps if you've already read the first three books in the Tiffany Aching series because it gives you some shorthand, but if you haven't, it doesn't really matter, there's more than enough explanation to tell the tale and suffice to say that nice Mr. Pratchett has hit one out of the park again.

Tiffany is now the witch of all the villages along the Chalk, not just her own little village anymore, and in the Discworld that means she's everything from a midwife to a vet, from social services to district nurse with the occasional bit of magic thrown in for good measure. Tiffany takes her work seriously and, although she knows she's more than just the hat, she also knows that people struggle to see her as more than that and when times are hard, the hat can become the focus for ill will. But for Tiffany, and for all witches, trouble is brewing. A malevolent spirit has been awakened, a wicked, jealous, hate-filled spirit that preys on folks fears, provoking hatred of witches and stirring up angry mobs ready for blood. But worse yet, Tiffany herself awoke the spirit and while the other witches might offer a word of advice here or there Tiffany must face the spirit down alone or risk losing her status as witch of the Chalk for good.

Once again Sir Terry has conjured a book that works on so many levels, due in large part to the amazing cast of characters with which he populates them. Small details in dress and mannerisms, even in the most throwaway players, truly illuminate his stories and, as always, his dialogue switches effortlessly from tremendously funny to tellingly perceptive to touchingly poignant at the drop of a (pointed) hat.

Tiffany herself has aged and matured beautifully over the course of the series and, despite never having been a teenage girl, Pratchett seems to know the mind of one incredibly well. In some ways she's wise beyond her years having lived around farms her whole life and been the centre of the community for many of them but in some ways she's also painfully naive like most teenagers her age.

While this book, like all of Pratchett's books, is woven throughout with his trademark light touch and great good humour, it's fair to say that the themes and issues this particular series deals with have matured along with their young protagonist and, while it may be marketed as a tome for teens, it deals, sometimes in some depth, with bigotry, domestic violence, suicide, jealousy and what a young bride is supposed to know on her wedding night. I only mention this so that the type of enlightened parent that gives their kids Pratchett to read can be ready for the inevitable questions.

That said you'll be cheering from the rooftops at the end, it's lovely and heart-warming and everything you could wish for but it's also tinged with a touch of sadness because it feels like the last we'll hear from Tiffany - at least in her own right - as if Mr P is sort of wrapping things up so he can move on, and while I'm sure he has a great any wonderful books still in him, I'd hate to think he's left this series behind because I've loved all of them.

I Shall Wear Midnight is published by Doubleday and is available from Amazon, Blackwell and all good book stores.

Terry Pratchett, as you might have guessed, has a website.