In July 1978, Dr. Wilbert Williams Jr. was standing on a street corner in Brooklyn, New York, afraid for his life. It had been less than three months since he was awarded a medical degree from Albany Medical College in upstate New York; yet there he was-enduring racial slurs from a group of angry white people who hated him simply because of the color of his skin. Even as the police stood guarding him, the group continued to taunt him with the words,...