Hello. Although you have not informed the book to which this question refers, by the context of the question and the names of the author and character presented, we can consider that you are referring to the book "Unbroken" written by Laura Hillenbrand.
In this case, we can say that the author interrupted Louie's narrative with information about Japan and Germany, so that the reader would understand the historical context of the narrative and have basic information to understand the events that would occur in the course of the narrative. This is because this book takes place in the Second World War and the involvement of Japan and Germany in this war will alter all of Louie's plans, in addition to being extremely impactful in his life, since because of the war he will be captured by Japan and become a guerrilla prisoner.
