One example of an arguable topic or theme in The Kite Runner is whether or not Amir has succeeded in redeeming himself over the course of the novel. I have taught this novel for several years, and I always have some students who feel like Amir has done enough to atone for his sins against Hassan, but other students believe Amir can never truly be redeemed because Hassan is dead, and Amir can never directly ask his forgiveness.
The novel begins with Amir's reflection on his past, and we know from the start that he feels immensely guilty for something that happened when he was a child in Afghanistan. His father's friend Rahim Khan has called Amir, and in addition to asking him to come to Pakistan to visit Rahim Khan, he suggests that Amir can "be good again" if he undertakes this journey. As we hear Amir's story, we learn of the ways that he wronged his friend Hassan, who, as an ethnic and religious minority and a member of the servant class, was oppressed by the culture around him but also harmed by Amir, who was his closest friend. When Amir feels insecure, he falls back on his own superiority (in terms of Afghan social structure) over Hassan. When he sees Hassan being assaulted by Assef and the two other boys after the kite-fighting tournament, and Amir does nothing to intervene or help Hassan, Amir reminds himself that Hassan is a Hazara who is below his concern. This is a way for Amir to attempt to shield himself from his own cowardice, which is the real reason he does not step in to help Hassan. After Hassan is assaulted, Amir frames him for stealing some of Amir's birthday presents to attempt to get him kicked out of the house. Amir is selfish; he does this because he cannot face Hassan every day after the way he betrayed his friend. Even though Baba forgives Hassan and asks him and his father, Ali, to stay, Ali says they must go, because they are insulted and cannot be made to live in that environment any longer. After Ali and Hassan leave, Baba and Amir eventually flee to Pakistan and then to California to escape violence in Afghanistan. Later, Amir does go to see Rahim Khan (Amir is now 38 years old; he was 12 when he betrayed Hassan) and learns that Hassan is dead but that he has a son, Sohrab, who Amir needs to get from an orphanage and bring to an American couple who will adopt him. It turns out that there was no couple, and Rahim Khan intended for Amir to adopt the boy. He also reveals to Amir that Baba was also Hassan's father. Amir is overwhelmed by the information and by his newfound responsibilities. However, after his initial resistance, he goes through with rescuing Sohrab, not just from the orphanage, but from Assef, who is now a Taliban leader. Amir is beaten to a pulp in the fight and endures great physical pain, but he feels he is cleansed through that assault. He fights to overcome many obstacles to bring Sohrab back to the United States, and even after they are in the home Amir shares with his wife, Soraya, he must defend Sohrab against the racism of his in-laws. Many readers feel like, symbolically, Amir has redeemed himself through these actions and that he is able to make up his past wrongs by giving Sohrab a good life.
Other readers, however, do not believe that Amir's sins are forgivable, and even if they are, they must be forgiven by Hassan. Since Hassan is no longer alive to grant this forgiveness, some readers think that Amir can never truly be forgiven. He can never go back and undo the damage to Hassan's life. Therefore, the extent to which Amir achieves redemption is a debatable topic in The Kite Runner.