After reading To Kill a Mockingbird, we can infer that Harper Lee used the title to highlight a central symbol in the novel. What/who does the...

The mockingbird is the symbolic centerpiece of the novel. Atticus notes that it is a sin to kill a mockingbird because, unlike the crows or bluejays, the mockingbird does not harm crops or attack other animals. All it does is make music. The symbolic message is that it would be a sin to inflict harm on the harmless. That fundamental principle can be applied to several characters.

First, Tom Robinson. He is shown throughout the story...

The mockingbird is the symbolic centerpiece of the novel. Atticus notes that it is a sin to kill a mockingbird because, unlike the crows or bluejays, the mockingbird does not harm crops or attack other animals. All it does is make music. The symbolic message is that it would be a sin to inflict harm on the harmless. That fundamental principle can be applied to several characters.

First, Tom Robinson. He is shown throughout the story to be courteous, helpful, gentle, and basically goodhearted. The "sin" would be (and is) convicting him of a crime he didn't commit.

Next is Boo Radley. At the point his character is introduced, damage has already been done to Boo, making him the person he is as an adult. The "sin" in Boo Radley's case would be arresting him for Bob Ewell's murder. While technically he did kill Ewell, it was out of an overarching goodness - his effort to save Jem.

In both cases, the characters are not evil, harmful or "bad" in any way. Symbolically, they are just making music.