What did Bryon and Mark learn from each other in That Was Then, This Is Now?

At the beginning of the novel, both Mark and Bryon are carefree teenagers who have fun at the expense of others. Although Bryon chooses to participate in illegal activities like drinking, gambling, and fighting, he understands there is a difference between right and wrong. In contrast, Mark has no regard for authority and is not sympathetic towards others. As the novel progresses, Bryon falls in love with Cathy and begins to spend less time with Mark. Bryon continues to mature and develop into a moral individual, while Mark remains ignorant and callous. At the end of the novel, Bryon calls the police on Mark after he discovers Mark has been selling drugs. When Bryon goes to visit Mark at the detention center, Mark tells Bryon that he hates him.

Mark learns from Bryon that his negative behavior has consequences. Bryon learns from Mark that certain individuals harbor negative feelings towards one another which makes forgiveness impossible. Bryon also learns doing the right thing is not always popular or recognized.