A compassionate, intelligent, perceptive white woman who had never before written a novel captured a white glimpse into a small but representative segment of black culture in a way that lit fires in the minds of millions of readers and boosted a movement already in motion. 

If a black writer could have made that impact they would have, but it took an inexperienced middle class white college dropout with a burning desire to expose injustice. Maybe it took a white writer to push the right buttons or avoid pushing the wrong ones in the white community. Maybe it took someone schooled in law to portray the injustice in an artful and compelling way. Whatever the combination, it worked. Boy did it work. That's not to say that Lee didn't have help. She had plenty of support from her editor, her friends and her family. But the book had her vision, her outrage, her courage, fire, talent and determination to see it through. 

What Harper Lee did that was so outstanding was to demonstrate or model for white Americans that it was okay, heroic even, to express outrage in public at other whites for their bigotry and injustice. She shamed them. Only a white writer could have been a model for other whites. Black leaders and writers were expressing their outrage, and that was effective, but white leadership in the realm of racial injustice was lacking. Lee's courageous novel provided a behavior breakthrough that unleashed a pent-up storm of outrage and guilt in the white community.