Nathan Radley is Boo’s older brother, and he takes over ownership of the Radley house after their father dies. Much like the rest of his family, Nathan is a rather elusive character whose motivations remain a mystery throughout the novel. He follows similar habits to those of his deceased father, such as walking into town every day and “[buying] cotton” for a living, so his arrival in Maycomb makes little difference. Scout and Jem also view Nathan as a replacement guardian of Boo, lamenting the fact that he has still never left the house.
While Lee never clearly defines the relationship between Nathan and Boo, Nathan’s two key scenes in the novel suggest that he wants to limit contact with the outside world. In Chapter 6, Nathan fires a shot into the air when he hears Jem, Scout, and Dill sneaking around in his backyard late at night. His quick and aggressive response in this moment highlights just how desperately he wants to maintain a sense of privacy in and around his home. The fact that he declares the next time will be a direct shot, regardless of who or what the intruder is, also emphasizes his lack of concern for others. Even more indicative of Nathan’s quest for isolation, however, is his decision to fill the knot in the tree where Boo and the Finch children had been exchanging small trinkets. He never admits to knowing about this form of communication, but his lie about the tree dying implies that he is aware of its function as a link between the Radley house and the outside world. Although Lee never offers a clear answer as to who this intense dedication to privacy is meant to benefit, the sense of mystery that Nathan’s character creates makes Boo’s appearance at the end of the novel even more surprising.