At the beginning of Harper Lee's To Kill A Mockingbird, Scout and her brother Jem are preoccupied with school, friends, and the spooky home of the mysterious Boo Radley. But this innocence is turned on its head when their father, a well-respected lawyer named Atticus Finch, agrees to defend a local Black man, Tom Robinson, from a false rape charge. The children's eyes are opened to the brutality and injustice of the racism in their hometown — and across the rest of the USA. For many readers, the lessons they learn from their father contain some of the most poignant messages of American literature.
To Kill a Mockingbird

Glossary
Bigotry - Prejudice towards a certain group, and an unwillingness to change your mind.
Pernicious - Harmful.