Handsome and ambitious, Mirella and Howard Cook-Goldman have it all-two precious children, dual careers, a great old colonial house on Massachusetts's North Shore, a golden retriever. The only thing they lack is reliable child care. <P> Enter Randi Gill, sent by Family Options, Ltd., an agency specializing in Midwestern girls with teaching aspirations ("Could you be Comfortable with Anything but the Best for Your Family?. . . Guaranteed Nationwide FBI Criminal Fingerprinting and Background Checks."). Randi's references are perfect. She's perfect. She cleans, cooks, sews, and makes her own Play-Doh. The children love her . . . almost too much. <P> Though it's hard for Mirella to watch Randi succeed with the children where she has failed, she can't deny the peace and order Randi has brought to the household. But perfection is a tough act to maintain, and soon enough, there are ruptures. When events force Mirella and Howard to reveal the secrets they've been hiding from each other, the family cataclysm catapults the nanny (who has secrets of her own) into <P> a position of unnatural control.<P> In A PERFECT ARRANGEMENT, Suzanne Berne now fixes her sights on contemporary, two-career family life. Overscheduled and overwhelmed, today's parents are desperate for help. Whatever child care they manage to set up, the arrangements are rarely perfect. This suspenseful novel asks a question all of them face: "Is there anyone you can trust with your children?"<P> <P> <P>