The relationship between Scout and Boo develops as she matures. At the beginning of the story, Boo is simply a frightening mythical being who does not really exist as a person. The children are fascinated by the macabre details of his story, and the mystery of him not leaving his house.
Jem gave a reasonable description of Boo: Boo was about six-and-a-half feet tall, judging from his tracks; he dined on raw squirrels and any cats he could catch, that’s why his hands were bloodstained—if you ate an animal raw, you could never wash the blood off. There was a long jagged scar that ran across his face; what teeth he had were yellow and rotten; his eyes popped, and he drooled most of the time. (Ch 2)
As the story continues, Scout and Jem begin to think about Boo as a person. They find the presents he leaves in the tree, and then Scout finds he has placed a blanket on her shoulders during the fire at Miss Maudie’s house. This baffling gesture shows even more that he wants to make friends.
Even though Scout sees him fully as a person, she is still curious about him. She no longer thinks of him as a monster, but as a mockingbird. She feels he is a victim of society, and most people don’t understand him.
Boo’s rescue of the children by killing Bob Ewell is the final step in cementing their friendship. When Scout and Boo finally meet, she treats him respectfully and carefully. She finally understands him. She says that letting people know that he saved them would be “sort of like shootin‘ a mockingbird.”
Atticus was right. One time he said you never really know a man until you stand
in his shoes and walk around in them. Just standing on the Radley porch was enough. (ch 31)