What genre is Philip Pullman's 'His Dark Materials' series often categorized under?

Philip Pullman's 'His Dark Materials' series is predominantly categorized as fantasy due to its rich and imaginative world-building, use of magical elements, and exploration of philosophical themes through the lens of a fictional universe. Fantasy as a genre often features fantastical beings, parallel worlds, and adventure that defy the laws of nature, all of which are prominent in Pullman's work.

The series includes elements such as daemons (animal companions that represent human souls), alternative realities, and metaphysical concepts, creating a narrative that strays from the boundaries of our reality and delves into the realm of the fantastical. While there may be aspects of science fiction in the exploration of different worlds and the nature of consciousness, it is the overarching presence of magic and the mythical that firmly place 'His Dark Materials' within the fantasy genre.

Other categories like historical or mystery do not resonate with the core elements of the story, which focuses on adventure, moral complexity, and the battle between good and evil in a richly imagined setting, all hallmarks of the fantasy genre.