Is To Kill a Mockingbird a racist book or not?

I think the book is one of the most powerful books against racism in my memory. Harper Lee was able to paint a picture of the social and ethnic prejudice in Southern small town America through a small book. Through her book she was able to illustrate the humanity behind prejudice and discrimination better than any historical text that I have ever read. Her characters bring the best of humanity (Atticus) with the worst of humanity (Bob Ewell) and paint the shades of grey underneath. From the plight of the gentle Tom Robinson to the private prison of Boo Radley to the pathetic victim that was Mayella Ewell, Lee was able to bring certain human truths out through the innocence of a little girl. Although the story is written in hindsight, we do grow up with Scout, Jem and Dill. WE see a very unfair world as well as certain heroic individuals who quietly make a difference.