Oprah Winfrey's public speaking career began in 1957. At three, she was speaking in church, by her teens she was touring the churches of Nashville, reciting the sermons of James Weldon Johnson. Other children sang, Oprah talked. And she's still talking -- but to much larger audiences. The path that led from her grandmother's farm in Kosciusko, Mississippi to becoming the first African-American woman billionaire is a story of unwavering focus and unrelenting determination. Taught to read by her grandmother at an age when most children are only learning to talk, Oprah became a...