LIFE LESSONS IN TO KILL A MOCKINGBIRD
People are not always as they first appear. Scout and Jem discover that first appearances can be deceptive, and it comes in part from Atticus's reminder that
"You never really understand a person until... you climb into his skin and walk around in it." (Chapter 3)
Boo Radley is the most obvious example: In the imaginative minds of the children, he is transformed from the town ghoul into a sympathetic neighbor before finally appearing before them in the flesh and becoming Scout's hero. Tom Robinson is another character who fits the can't-judge-a-book-by-its-cover mold. The children know he has been accused of raping a white woman, and they assume that since he is black and because of "his broad shoulders and bull-thick neck. He could easily have done it." Jem and Scout don't think much of Dill at first--he is "puny" and not "much higher than the collards"--but they quickly become best friends. Dolphus Raymond is another example: He fools the entire town as he deliberately stumbles and sips from an apparent bottle of whiskey hidden in a bag. The bottle contains no alcohol, and Scout and Dill learn that Dolphus is hardly mentally deranged.
Teachers can't always be trusted. Scout has real bad luck with her teachers. Miss Caroline proves that a college education doesn't necessarily equate with competence, and she makes Scout's first day at school one to remember for all the wrong reasons. Scout is quick to see that Miss Gates doesn't always practice what she preaches: The teacher criticizes Hitler's persecution of the Jews but is overheard making hateful comments about Maycomb's Negroes.
"It's a sin to kill a mockingbird." Scout doesn't fully understand Atticus's warning about what she and Jem cannot shoot with their air rifles, but after Miss Maudie explains it to her, it becomes clearer. It simply means that no one should kill an innocent being--human, animal or insect. Scout recognizes that at least two of the story's tragic characters--Tom and Boo--fit the mockingbird mold, and she agrees with Sheriff Tate's decision to keep Boo's actions out of the public eye.
"... it'd be sort of like shootin' a mockingbird, wouldn't it?" (Chapter 30)