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 book's main focus is on the clash between a son's passion for manga, anime, and technology versus his father's interest in Japanese history and tradition. Additionally, the narrative highlights the difficulties Carey encounters when navigating Japanese culture as a foreigner.