Bruno's confusion surrounding the situation at "Out With" is an example of Boyne's technique of defamiliarization. Through the voice of a limited, third-person narrator, Boyne leads the reader to Auschwitz and introduces the terrible things taking place there as if the reader has no prior knowledge on the topic. This allows the reader to avoid immediately categorizing the victims of the Holocaust as "Others," fundamentally different and unknowable. Rather, the reader gains the perspective of Bruno's childlike innocence.
Some critics have criticised the premise of the book and subsequent film. Reviewing the original book, Rabbi Benjamin Blech wrote: "Note to the reader: There were no 9-year-old Jewish boys in Auschwitz – the Nazis immediately gassed those not old enough to work."  Rabbi Blech affirmed the opinion of a Holocaust survivor friend that the book is "not just a lie and not just a fairytale, but a profanation." Blech acknowledges the objection that a " fable " need not be factually accurate; he counters that the book trivialises the conditions in and around the death camps and perpetuates the "myth that those not directly involved can claim innocence," and thus undermines its moral authority. Students who read it, he warns, may believe the camps "weren't that bad" if a boy could conduct a clandestine friendship with a Jewish captive of the same age, unaware of "the constant presence of death."