What are some reasons that support the idea that Boo Radley has courage?

Throughout the novel, Boo Radley is a reclusive, shy individual who rarely leaves his house. He was raised in a home with religious radicals who refused to let him outside. At the beginning of the novel, Boo gives Scout and Jem several gifts in the knothole of the tree in his front yard. Scout describes two of Boo's gifts by saying, "Our biggest prize appeared four days later. It was a pocket watch that wouldn’t run, on a chain with an aluminum knife" (Lee 38). Despite his brother's strict rules to stay inside the house, Boo ventures out of his home in an attempt to form a friendship with the Finch children. Boo's actions are courageous because his brother is known to be a strict individual who doesn't shy away from confrontation. Boo knows that he will probably be punished for leaving his house, but decides to venture outside anyway.

At the end of the novel, Scout and Jem are walking home from a Halloween festival when Bob Ewell viciously attacks them. Boo Radley courageously leaves the comfort of his home to intervene and fight Bob Ewell off of the children. During the struggle Scout mentions,

"He slowly squeezed the breath out of me. I could not move. Suddenly, he was jerked backwards and flung on the ground, almost carrying me with him. I thought, Jem's up" (Lee 160).

Scout is unaware that Boo Radley was the individual who pulled Bob Ewell off of her during the struggle. Boo successfully wrestles Bob away from Jem and Scout and stabs Bob with his own knife, killing him.

Once Boo returns Jem to the safety of the Finch residence, Scout gives her description of the attack to Sheriff Tate. In Chapter 29, Scout mentions that someone pulled Bob Ewell off of her, and when Tate asks Scout who it was, she says, "Why there he is, Mr. Tate, he can tell you his name" (Lee 164). Scout then points to Boo Radley, who is quietly standing in the corner. Sheriff Tate then tells Atticus that Bob Ewell fell on his own knife, but Atticus refuses to believe him and thinks Jem stabbed Bob. Tate finally says to Atticus,

"I never heard tell that it’s against the law for a citizen to do his utmost to prevent a crime from being committed, which is exactly what he did, but maybe you’ll say it’s my duty to tell the town all about it and not hush it up. Know what’d happen then? All the ladies in Maycomb includin’ my wife’d be knocking on his door bringing angel food cakes. To my way of thinkin’, Mr. Finch, taking the one man who’s done you and this town a great service an’ draggin’ him with his shy ways into the limelight—to me, that’s a sin" (Lee 169).

Sheriff Tate indirectly says that he knows Boo Radley killed Bob Ewell out of self-defense but refuses to speak about Boo's heroics because it will draw unwanted attention to Boo. Boo saved the children's lives during a dangerous struggle with an armed man. Boo's actions are yet another reason to support the idea that he is courageous.