Nora Ephron's new collection, I Remember Nothing (Knopf), reads like a swan song: It begins with the title essay, about age-exacerbated memory loss, and ends with two lists, "What I Won't Miss" and "What I Will Miss." In between are reflections upon loved ones lost, and at least one autumnal contemplation of the perfect day: "A frozen custard at Shake Shack and a walk in the park. (Followed by a Lactaid.)" Not since Bob Dylan sang "It's not dark yet / But iiiit's gettin' there" has a major American voice weighed in so, uh, merrily about pending mortality. But here's hoping that Ephron, who will turn 70 next year, has at least a few more terrific books and movies in her. If it's any comfort, Dylan recorded "Not Dark Yet" 13 years ago.