There are many characters in To Kill A Mockingbird that suffer lonliness and isolation. In fact nearly all of the characters are lonely or isolated in some way. Most obviously isolated is Boo Radley who almost never leaves his home but reaches out to Scout and Jem leaving gifts in the tree, giving Scout a blanket at the fire, and helping escape Bob Ewell's attack. Mayella Ewell is another prime example of an isolated character. She is isolated from the town because she is a Ewell, but she is isolated from her family by her love of beauty and her desire for company. Her isolation and lonliness were evident in her testimony. She did not even know how to answer Atticus when he asked if she had friends or if she loved her father. She obviously did not even understand the concept of friendship or love. When Tom Robinson was describing how he helped her when noone else would, Scout's heart went out in response: "it came to me that Mayella Ewell must have been the lonliest person in the world."
While Boo and Mayella are obviously isolated, many of the other characters are isolated in less obvious ways. Atticus is isolated by his decision to defend Tom Robinson. Scout is isolated by her intelligence. Mrs. Dubose is isolated by her illness. Dill is isolated by his poor family situation. Isolation and lonliness play a major role in many of the character's lives in Harper Lee's novel.