What do you actually know about Arthur "Boo" Radley at this point in the book (chapter 4)

By the end of Chapter Four, Boo remains a mystery. To the children, Boo is only what they have heard from popular legend, and interpreted in their own imaginations. Scout's retelling of Jem's description of Boo shows how her young mind could not yet distinguish between fact and fiction. Jem explains that Boo, "dined on raw squirrels and any cats he could catch, that's why his hands were blood-stained - if you ate an animal raw, you could never wash the blood off." The children's acceptance of such superstitions as the permanence of raw animal blood shows that they are equally susceptible to accepting the local gossip about the mysterious Boo, as evidenced by Scout's evaluation of Jem's description as "reasonable."