Where could I hide my Scarlet Letter?"" Is she wearing it on her sleeve? She is Nan, another one of Violet Weingarten's graceful, bewildered and slightly timid women who as in earlier books are versions of herself or yourself as they try to deal with situations and more modern times which have outdistanced them. Now she learns what everyone else knows--that her husband is leaving her for what used to be a ""lollipop"" and is now a ""relationship."" She thinks of all the kinds of things she's read from Chekhov to Colette to Willa Cather. She talks with friends; her son Bob whose ex-wife Rachael is actually much closer to her; to her daughter Sally, furiously aligned on her side; to a lachrymose lover of her youth; to her shrink. She remembers a still earlier past--that of her parents. Often she looks at the blank paper in her typewriter as she tries to write again, and sometimes you suspect, perhaps unfairly, that Mrs. Weingarten has had trouble cajoling her ideas and feelings into firmer shape. This is not her most instantly ingratiating light novel (Nan is both too vulnerable and too discreet at the same time), but many women of middle years will find that it readily identifies what every woman knows or learns while picking up the crumbs of that half a. . . .