It's hard to pick the best book in Pullman's His Dark Materials trilogy. The Golden Compass is a fascinating if somewhat arduous introduction to Lyra's world, full of daemons and airships and armored polar bears, while The Amber Spyglass takes the biggest narrative risks (not all of which pay off). But The Subtle Knife is a fast-paced romp through the multiverse, unburdened by the setup and windup duties that sometimes weighed down the first and third books in the series.