His dark materials

"Lyra is content to run wild among the scholars of Jordan College, with her daemon familiar always by her side. The arrival of Lyra's fearsome uncle, Lord Asriel, to Jordan College draws her to the heart of a terrible struggle-- a struggle born of Gobblers and stolen children, witch clans and armored bears. As she hurtles toward danger in the far North, young Lyra never suspects the shocking truth"--Container.

Lyra and Will find themselves at the center of a battle between the forces of the Authority and those gathered by Lyra's father, Lord Asriel. The final book in the Dark Materials trilogy is now available in trade paperback. Lyra and Will are in danger, but with help from Iorek Byrnison, the armored bear, and two Gallivespian spies, they must journey to a dark world where no living soul has gone. Meanwhile, Dr. Mary Malone builds an amber spyglass...

In a time before Lyra Silvertongue was born, the tough American balloonist Lee Scoresby and the great armoured bear Iorek Byrnison meet when Lee and his hare daemon Hester crash-land their trading balloon onto a port in the far Arctic North and find themselves right in the middle of a political powder keg. Fantasy.