As the novel progresses, the children’s changing attitude toward Boo Radley is an important measurement of their development from innocence toward a grown-up moral perspective. At the beginning of the book, Boo is merely a source of childhood superstition. As he leaves Jem and Scout presents and mends Jem’s pants, he gradually becomes increasingly and intriguingly real to them. At the end of the novel, he becomes fully human to Scout, illustrating that she has developed into a sympathetic and understanding individual. Boo, an intelligent child ruined by a cruel father, is one of the book’s most important mockingbirds; he is also an important symbol of the good that exists within people. Despite the pain that Boo has suffered, the purity of his heart rules his interaction with the children. In saving Jem and Scout from Bob Ewell, Boo proves the ultimate symbol of good.