After Scout escorts Boo back to his home, she pauses on the Radley porch and, remembering her father's advice about how "you never really know a man until you stand in his shoes and walk around in them," she looks out across her neighborhood. Standing on Boo's porch in Boo's shoes, Scout now sees her little world from Boo's eyes, as if it is he standing there (or peering through the window), watching the events of the past two years. She understands that Boo has probably seen much of the children's activities, and standing there she remembers them more vividly than ever before: running to meet Atticus, acting out the Radley Game, fighting on the sidewalk, finding gifts in the secret knothole, and watching Atticus kill the mad dog. But it is Boo seeing them now:
Summer, and he watched his children's heart break. Autumn again, and Boo's children needed him. (Chapter 31)
Scout "sees" that Boo has been watching over Jem and Scout all along--keeping his eye on them even when they do not see him--and that they have become his children, too. She understands now that Boo must have lived up to his reputation as a nocturnal prowler, but probably only for the good deed of being their protector against the evils that exist, even in their little world.
It is interesting how Harper Lee's novel begins and ends with keen interest in Boo Radley as he has materialized from being a "haunt," or spirit, to a real person in the flesh who has performed a truly heroic deed.
As Scout stands on the Radleys' porch, she is able to look across the street and objectively view her house in its relationship to the others. She now realizes Boo's home is not as strange as she previously believed it. She considers that she has only entered the Radleys' yard two times while she has been at Miss Maudie's numerous times. Scout reflects that Boo has left them personally-fashioned gifts; most of all, she realizes Boo has saved her and Jem's lives, while they have made a game of sneaking into his yard and spying upon him, as well as thinking ill of him. They have given Boo nothing in return for his generosity.
Neighbors bring food with death and flowers with sickness and little things in between. Boo was our neighbor. . . But neighbors give in return. We never put back into the tree what we took out of it: we had given him nothing, and it made me sad.
Memories of the past year rush into the mind of Scout, and she feels guilty about the attitudes and treatments of Boo that she and the boys dealt him when all the time he only wanted to share in their happiness.