The Golden Compass (His Dark Materials, Book 1) By Philip Pullman

Here lives an orphaned ward named Lyra Belacqua, whose carefree life among the scholars at Oxford's Jordan College is shattered by the arrival of two powerful visitors. First, her fearsome uncle, Lord Asriel, appears with evidence of mystery and danger in the far North, including photographs of a mysterious celestial phenomenon called Dust and the dim outline of a city suspended in the Aurora Borealis that he suspects is part of an alternate universe. He leaves Lyra in the care of Mrs. Coulter, an enigmatic scholar and explorer who offers to give Lyra the attention her uncle has long refused her. In this multilayered narrative, however, nothing is as it seems. Lyra sets out for the top of the world in search of her kidnapped playmate, Roger, bearing a rare truth-telling instrument, the alethiometer. All around her children are disappearing-victims of so-called "Gobblers"-and being used as subjects in terrible experiments that separate humans from their daemons, creatures that reflect each person's inner being. And somehow, both Lord Asriel and Mrs. Coulter are involved.