The concluding volume of His Dark Materials resolves the trilogy's theological and philosophical argument in terms that engage directly with Milton's Paradise Lost, staging a confrontation whose outcome determines the nature of consciousness across all worlds. The novel is the longest and most ambitious of the three, opening up the land of the dead, introducing the Mulefa - wheel-using creatures whose relationship with Dust offers a key to understanding its nature - and giving Mary Malone a part in the resolution that no one but the dark matter physicist could play. The Amber Spyglass is Pullman at his most explicit about his philosophical concerns, and its emotional climax is among the most affecting in contemporary fiction for any age.