These are three of the major themes discussed by author Harper Lee in her novel To Kill a Mockingbird. There are many different examples.
PREJUDGMENT. Many of the various characters are prejudged due in part to social bias and expectations. Scout's immaturity is evident throughout much of her narrative. Boo Radley is probably the best example; rumors about his unusual behavior make him out to be some sort of monster, but those few people who have contact with him know better, as Scout discovers in the final chapters. African-Americans are blamed for most unexplained circumstances in the town, and Dolphus Raymond is presumed to be mentally unbalanced because of his preference to live with Negroes.
PREJUDICE. Racial prejudice is rampant in TKAM. African-Americans are scorned by most (but not all) of Maycomb's white population. Many of the town's white families (the Ewells and Cunninghams) are also treated with disdain; likewise, women do not receive social equity. The mentally unstable are also looked down upon.
SOCIAL EXPECTATIONS. There are several different social classes evident in Maycomb. Jem describes the four different "peoples" as people like the Finches and their neighbors; people from Old Sarum, such as the Cunninghams; people like the Ewells; and Negroes. Aunt Alexandra particularly does not approve of mixing with any of the last three groups, though Atticus mixes freely with them all (though he, too, is not fond of the Ewells).