Ephron wrote the Broadway play Imaginary Friends, about the feud between Lillian Hellman and Mary McCarthy, and was most recently represented on stage as the co-author of Love, Loss, and What I Wore. In addition, she had written the play Lucky Guy, about journalist Mike McAlary, which has been eyeing a Broadway run.
She was a noted essayist, author, screenwriter, and filmmaker, whose many works include Heartburn, Julie & Julia. You've Got Mail, Sleepless in Seattle, Silkwood, and When Harry Met Sally.
She is survived by her third husband, Nicholas Pileggi, her sons, Jacob Bernstein and Max Bernstein, and her sisters Delia Ephron, Amy Ephron, and Hallie Ephron.