Nothing But the Truth is a documentary style novel, meaning that the author relays the events of the story through layers of different kinds of documents: transcripts of conversations or telephone calls, memos, journal entries, letters, newspaper articles. By showing so many different perspectives or points-of-view, Avi makes a clear argument that there is no one true side to a story or only one 'truth' to what happened.
Readers must decide for themselves what is true and not true by paying attention to the details in the various documents. For example, after Philip gets in trouble in Miss Narwin's home room class, the reader sees both his and Narwin's version of the story. Philip's story that he concocts to explain his actions to his parents seems to be much less truthful--he leaves out important details like Miss Narwin asking him repeatedly to be quiet and respectful and the fact that there is a 'silence' rule--because he does not want to get in trouble at home. The reader must weigh the actual events and details for themselves. Did Philip break the rules? Yes, he was not respectfully quiet during the announcements. Did Miss Narwin give him several warnings? Yes, he was warned multiple times. These facts, however, become lost in the shuffle after Philip conveys a very one-sided story to his parents about how his overly strict English teacher will not let him exercise his patriotic rights. Avi's novel demonstrates how the true facts of an event can get lost and even buried as different perspectives and opinions distort the 'truth' of what really happened.