The writing process of Philip Roth: “I invent a character as I go along,” he says. “You must find everything about this man. Who he is, where he’s from, what he’s done, what his family is.”

Roth says, “There’s a journalistic side to writing novels,” in mixing real life with fiction. “You can’t invent off of nothing.”

Philip Roth: Unmasked premieres nationally Friday, March 29 on PBS (check local listings)