Banbury Cake reports that Philip Pullman, the author of the His Dark Materials trilogy, has written a book which occurs before the events in The Golden Compass (which was published as Northern Lights in the UK). Once Upon A Time in the North will be published in the spring by Random House.
Pullman told the paper that the new short book is "a separate story that takes place some time before Lyra was born involving the two characters Lee Scoresby, the balloonist, and Iorek Byrnison, the armoured bear. You will be able to read about their history and how they first met. You see when we meet them in Northern Lights they have known each other for years and fought in various campaigns together."
The next full-length novel from Pullman, currently titled The Book of Dust, is set to be published in 2009.
h/t Bruce at Bookshop Blog.