The Subtle Knife(His Dark Materials 2)

The Subtle Knife, the second novel in the book 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.
The book focuses more on the characters and their own individual plots, rather than just on Lyra's father, Lord Asriel, and his war against the Magisterium. It describes not only Lyra and Will's journey, but also the journeys of Lee Scoresby and Serafina Pekkala. In addition, Pullman alludes heavily to the study of dark matter (or "Dust") and particle physics to further establish his metaphysical saga.