On Saturday Extra's final show of the summer break:  Our best conversations with authors of notable books. CNN's Jake Tapper on one of the most fateful decisions in American history - Joe Biden's decision to run for re-election despite evidence of his decline; actor Griffin Dunne on coming of age in a family of larger-than-life characters in Hollywood; and historian Sophia Rosenfeld on the history of how choice became synonymous with freedom and self expression.