A year in the interconnected lives of four women, three around the Maginot Line of middle age (40 even if they feel like 30) and all looking for something new to refresh and redirect their lives with or without husbands. And as you will know from the prologue, an unanticipated death awaits one of them--it might have been any. There's Ellen with an Arrow-stuffed-shirt husband and two teenagers (anorexic Jill figures in the story) and many lovers until one abandons her first; Nikki, editor, who leaves her Connecticut home to take an apartment and have an affair in the city; Margot, anchorwoman, who never finds ""Mr. Right,"" certainly not the 23-year-old stepson of Rachel Fowler; and Rachel, the wife of an international banker who finally frees her from dinner parties to go to college. This is all such easy entertainment (you can add and subtract and subdivide it on your pocket calculator) but Rona Jaffe handles it with an enviable assurance for all those women who sleep on Wamsutta only to dream of Porthault. . . . A sure sure thing.