The Subtle Knife by Philip Pullman

The Subtle Knife, the second novel in the His Dark Materials series, was written by English novelist Philip Pullman and published in 1997. The novel continues the adventures of Lyra Belacqua as she investigates the mysterious Dust phenomenon and searches for her father. Will Parry is introduced as a companion to Lyra, and together they explore the new realms to which they have both been introduced.