The Ropemaker - Peter Dickinson
I picked this one up at the library because I liked the sound of the blurb but sadly, it was an immense disappointment and I got bored with it about halfway through.

Tilja and her family live in the Valley, an area that was surrounded by an impenetrable forest to one side and a glacier to the other, placed there by magic to protect them from the ravages of the Empire and raiding tribesmen. As part of the magic, a woman of Tilja's family has the job of singing to the trees, while another family has the hereditary role of singing to the snows, in order to keep the magic going. However, it's starting to break down, exposing the families who live in the Valley to danger for the first time in many generations.

Tilja's talents lie in other areas, in that she appears to be very much the Anti-Magic, in that she can hold something magic and hide its presence so it can't be detected. Along with her grandmother and two representatives of the other family, Tilja sets off into the mysterious Empire to find a magician to renew their magic.

It's a fantastic idea, and the Empire is quite scary in its bureaucratic niceties (like taxing people for permission to die, forcing them to go to a particular place to do so and fining their families if they don't get there), but sadly the characterisations leave much to be desired. I was left really not caring whether any of the characters lived or died - Tilja is very two-dimensional and the boy from the other family appears to be there in a spear-carrier role and nothing more. I can't say this has filled me with enthusiasm to look out anything else from Dickinson, since I can't bear to see a good idea go to waste...