Who is Robert Bob Ford from The Assassination of Jesse James by the Coward Robert Ford and what is their importance?

Robert (Bob) Ford is the man who shoots and kills Jesse James. Bob is only nineteen years old when he first goes on a train robbery with Jesse James. He talks with Frank then tries to convince Jesse that Frank agrees that Bob should be Jesse's "apprentice" during the train robbery. Bob needs to be constantly in the limelight and seeks to be in positions that garner the most attention.