The main theme of the book is the contrast between the son, mostly interested in manga, anime, and technology, and the father, interested in Japanese history and traditional culture. Another important aspect of the book is the difficulty Carey encounters in his attempts as a foreigner in understanding Japanese culture.
The central theme of the book revolves around the contrasting interests of a son who is drawn to modern media (manga, anime, technology) versus his father's interest in traditional Japanese history and culture. The story also emphasizes the challenges Carey faces when trying to understand and integrate into Japanese society as an outsider.