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

Scout, Jem, and Boo actually know little about Boo Radley. What they've heard about him is based on gossip and hyperbole..... exaggerations and the things they hear while out amongst the community. Over the course of the first several chapters..... Boo becomes larger than life. The only thing the children are sure of is that he exists.