A SECRET WORD: The late Groucho Marx...

A SECRET WORD: The late Groucho Marx didn’t save his sharp wit just for the movies or “You Bet Your Life.” A new book of his never-before-published letters, edited by his daughter, Miriam Marx Allen, 64, of San Clemente, shows him that way at home too (E1). . . . A sample from 1947, when she was away at college: “Let’s hear from you from time to time. Your letter is one of the few letters I get that isn’t a bill, although even that one frequently is.”