Through all the head-shaking, quelling of nausea and Jem-yelling, I had heard another sound, so low I could not have heard it from the sidewalk. Someone inside the house was laughing.

– Harper Lee

To Kill a Mockingbird, Chapter 4. Scout lands at the bottom of the Radley’s front steps when a tire she is inside rolls into their yard. She hears laughter coming from the house. It can only have been Boo Radley. He is watching the children, this signals how he will later make an critical intervention in their lives.