The main theme of To Kill a Mockingbird is growing up in a small town in the Deep South during the Great depression. Scout Finch is a very intelligent, sensitive girl, spunky. Everything that happens is seen through her point of view. This includes all the dramatic material about racial prejudice, judicial injustice, rape, and attempted murder. The novel might be called a feminine version of Mark Twain's The Adventures of Tom Sawyer. There was a murder and a murder trial in Mark Twain's book too, and there was a defendant who had been falsely accused of the crime. The biggest event in Harper Lee's novel is, of course, the trial of an innocent man and his defense by Scout's courageous father--but the main theme is nevertheless the inner life of a very young girl over a period of several years of boredom, growing pains, relations with juvenile peers, sporadic excitement, and tragedy.