One is never too old for a Pullman masterpiece, and this trilogy proves it. It has complex characters drawn with daemons—aspects of personality externalized into various forms of animal life (mammals, birds, insects, etc.) who operate as intelligent partners to the primary characters. Rich in detail and consistent elaboration of species features.
Philip Pullman has an endless ability to fashion intriguing and provocative turns in the story that get one thinking deeply about one's own life, over and over. No black-and-white all-good or all-bad personalities to flatten the story into one more tired rerun of over-used themes.
Don't miss this if you have any taste for imaginative metaphoric stories.