Dave Davies

The actor, who's currently starring in Glenngarry Glen Ross opposite Al Pacino, has been acting for the stage since he was a teenager in Union City, N.J. "It was the only thing I ever wanted to do, really," he says.

On the hit PBS Masterpiece series, the social rules the characters have always known are changing as the world events of the 20th century unfold. The series' creator, Julian Fellowes, says his relatives who lived through that era inspired his lasting interest in class.

In a new book, biographer David Nasaw profiles the father of Robert, John and Teddy, and unpacks the elder Kennedy's influence on his children. "He told them over and over again, 'I'm making all this money so you don't have to make money, so that you can go into public service,'" Nasaw says.