Perhaps the most important example regarding "truth" in the novel is spoken by the protagonist, Steve Harmon.

Truth is truth. It's what you know to be right.

This example calls question to Steve.  The truth is the truth, but it is not what "you" know to be right. It is what everyone knows to be right.  Here, one could question Steve on his understanding of the truth.  This example shows that Steve could make something true for himself if he alone knows it to be right.

What's the truth? Anybody in here knows what the truth is? I don't know what the truth is!

This example is provided per the VO (voice over) of Inmate 1.  This is perhaps one of the most intriguing quotes from the text regarding truth.  The inmate is stating what many feel.  Once involved in the judicial system, the truth lies in the hands of the court system (the jurors, the lawyers, and the judge).  Think about it this way, many people have been found guilty of crimes that they did not commit, but the fact that they are convicted makes it a truth to the community.  But is it really?

Basically, as much as many would like to believe that "truth" exists, truth is subjective.  The novel embraces this and runs with it.  Throughout the novel we, as readers, are expected to have compassion for Steve.  We are expected to trust in him, believe him.  The idea of what is truth comes under fire by everyone involved in the novel- including the reader.  Therefore, there is no other better true judge of how the concept of truth impacts a reader than the reader him/herself.