In 'To Kill a Mockingbird', what is the real name of Boo Radley?

In 'To Kill a Mockingbird', Boo Radley's real name is Arthur Radley.

Arthur is the reclusive neighbor who becomes a mysterious figure in Scout and Jem Finch's childhood. Maycomb's children imagine frightening stories about him, but those rumors contrast sharply with his quiet kindness. He secretly leaves small gifts for the children in a tree's knothole and watches over them from a distance.

Arthur's role becomes crucial near the novel's climax, when he rescues Scout and Jem from Bob Ewell's attack. Scout's eventual encounter with him changes her understanding of the rumors surrounding the Radley family. The name Boo is therefore a nickname, while Arthur Radley is his given name.

A common mix-up is Nathan Radley, who is Arthur's brother. Nathan is the adult who seals the tree knothole, cutting off Arthur's attempts to communicate with Jem and Scout.