What is the theme in Cash: The Autobiography by Johnny Cash?

Need for honesty is another theme in the book. Johnny says that he wants his music to be popular, but wants it to be - above all else - honest. He also says that he, Luther and Marshall were not overly talented on the point of being able to put together musical scores for new songs. While he says that this does limit him, he says that he doesn't really regret it. He also points out that they could have learned, given the drive and opportunity, but that he was somewhat lazy about making the effort to do so. He ends that particular thought by saying that their music was, first and foremost, honest, and that as he looks back on it, he's not ashamed of their performances for that reason alone.