Analyze the main characters, Bryon and Mark, in That Was Then, This is Now.

Bryon Douglas: Liked by others, he is personable and has no problems picking up girls, although, he can be insecure. Because he is a hard worker and a deep thinker, he is a good student in school. He is extremely close with this best friend and adopted brother, Mark.

Bryon is a dynamic character because of the changes he goes through throughout the novel. In the beginning he is extremely close with Mark; however, by the end of the novel Bryon makes a mature decision and calls the cops on Mark for selling drugs to children.

Mark Jennings: His persuasive demeanor allows him to get away with things. Mark has an intense closeness with Bryon, as he sees Bryon as his only family. His early life was rough, and as a result, there is a wildness to him as well as a disregard for rules. With no moral fibers, Mark makes choices that ultimately lead to his downfall.

Mark is a round character, as author S.E. Hinton fully developed who he is in a way that makes him complex in his actions; however, he also a static character as he does not grow or change much throughout the course of the story.

BRYON DOUGLAS.  The narrator of the novel, Bryon tells the story of the collapse of his close friendship with his foster-brother, Mark. Although both boys spend a great deal of time away from home and roaming the streets, looking for trouble (due in part to their dysfunctional, single parent home life), Bryon eventually tires of this scene. His love and loyalty for Mark are strong: He tends to Mark's injuries after a fight and willingly accepts a beating that is meant for Mark. But Bryon begins to change after talking with Mike Chambers in the hospital; Chambers tells him how he is beaten but chooses not to seek revenge. The guilt over how Bryon lives his life increases after his friend Charlie is killed while helping Bryon and Mark. He matures further after he falls in love with Cathy, sees his mother hospitalized, and decides to get a job. But the toughest decision of his life comes when he turns Mark in for drug dealing after his friend, M&M, overdoses on LSD. Bryon questions his own motives for having Mark arrested, but he testifies against him and then visits him in prison. Bryon sees that Mark has changed for the worst, and Mark tells him that their friendship--"that was then, this is now"--is over. In the end, Bryon--having lost both Cathy and Mark--wishes he were young again, when life and its problems seemed so much simpler.

MARK.  A boy with a terrible past, Mark is taken in by Bryon's mother after Mark's parents kill themselves during a drunken brawl. Mark loves Bryon like a brother, and he enjoys the gang life they lead during their early teens. But while Bryon seems determined to make a change in his life, Mark prefers the status quo. Mark seems to have little regard for what is right and wrong, and when Bryon begins spending time with Cathy instead of him, Mark becomes jealous. Mark turns to selling drugs, for which he shows no remorse. He grows to hate Bryon after his arrest, and his behavior while in the juvenile detention center is so bad that it appears he will eventually be sent to an adult prison. As Bryon seeks to improve his life and make amends to Mark, Mark never wants to see his friend again, and he seems intent upon destroying himself behind bars.

What differentiates Mark and Bryon in That Was Then, This Is Now?

One of the differences in attributes between Mark and Bryon is their sense of moral righteousness.  Even in their penchant for mischief, there is a difference between them.  Bryon's attributes served him as the "hustler," while Mark's served him as the "thief."  This highlights the differences in terms of where they are on the moral spectrum.  Mark is closer to being irredeemable, while Bryon demonstrates a propensity for maturation and reflection.  Mark's attributes enable him to sell drugs, a line that Bryon cannot cross.  

It is in this difference in characterization where their divergence takes place.  Mark feels that there is no need to change and wishes to go back to the past, a time where he and Bryon were happy getting into trouble.  The terse response that Bryon gives of "that was then, this is now" serves to highlight how he is changing. Bryon's propensity for change is what enables him to turn Mark in for selling drugs and send him to jail.  Bryon's maturation and embrace of change is what causes him to feel so fundamentally alone at the end of the novel, a reminder that what he said was true in how "that was then, this is now."  The traits of maturation and willingness to embrace what is as opposed to what is are where Mark and Bryon possess fundamentally different attributes.