FRONTLINE: The Choice, which draws on in-depth interviews with the advisers, friends and those closest to these unlikely candidates, as well as with seasoned observers of American politics, who together tell the definitive story of these men and their ascent to their party's nominations. It has been called one of the most historic presidential elections in our nation's history, Barack Obama versus John McCain. It is a race that pits the iconoclast against the newcomer, the heroic prisoner of war against the first African American nominated by a major party.