Family
Family is perhaps the most significant theme in the novel. At the start of the novel, Christopher (its main character and protagonist) travels to visit his grandfather, who he rarely speaks to. There, he hopes to bond with his grandfather and get a better sense of him and his family's history. But Christopher gets more than he has bargained for. He learns about his grandfather's power as the guardian of the normal, non-magical world and Archipelago. While helping his grandfather save both worlds, Christopher learns about the importance of staying close to family and maintaining connections to the people that love you. Without that, he learns the world but be a worse place.
Magic
Magic plays an important role throughout the story. After meeting up with his grandfather, Christopher learns of a world unlike his own that is filled with magic (and magical people). To that end, when he meets a young woman named Mal, Christopher learns of the splendor of magic. For instance, Mal has obtained a flying coat as she attempts to obtain a baby griffin. This magic at first petrifies and perplexes Christopher, but he eventually becomes used to it, showing the human spirit's ability to adapt to new situations (and even appreciate them).
