What do Scout, Jem, and Dill know about Boo Radley?

Miss. Maudie tells the children that Boo is alive, and that he stays in the house. She tells Scout that Boo was a pleasant and well-mannered child.

“Arthur Radley just stays in the house, that’s all,” said Miss Maudie. “Wouldn’t you stay in the house if you didn’t want to come out?”

“No, child,” she said, “that is a sad house. I remember Arthur Radley when he was a boy. He always spoke nicely to me, no matter what folks said he did. Spoke as nicely as he knew how.”