Four decades ago, Erica Jong introduced the world to the term “zipless” sex, that is, casual, no-strings-attached encounters with near strangers. Her book “Fear of Flying” became synonymous with female sexual liberation, and turned Jong into a feminist icon. Now, Jong takes on the subject of sex after 60. Her new novel, “Fear of Dying,” tells the story of Vanessa Wonderman, a former starlet who is forced to confront the realities of aging and decline. She thinks casual sex can stave off her growing preoccupation with mortality and turns to a website to find it. Author Erica Jong talks with Diane about death, feminism and 40 years of writing