Belva Plain, Author Delacorte Press $22.95 (360p) ISBN 978-0-385-31104-5

Writing with her customary fervor but with uneven results, Plain ( Whispers ) again investigates the familiar territory of complex family relationships. This time she examines a situation right out of recent headlines: the switching of babies at birth. Margaret and Arthur Crawfield have just buried their son Peter, dead of a genetic disorder, and must come to grips with the fact that DNA testing proved conclusively that he could not have been their biological child. The parents of the dead boy, Bud and Laura Rice, are quickly traced, and it is shown that their robust son Tom is indeed the Crawfield's. But--and the irony is heavily emphasized--Tom and his father are both racists, admirers of the Klan and the Nazi party. The Crawfields are Jewish. The novel is at its best, and most moving, as the two families meet and try to sort out the events that have devastated them all. Bud evades the issue by total denial. Depressed and antagonistic, Tom emerges as one of the few fully realized characters in this schematic rendering. Unfortunately, most of the other characters are stereotypes: the loyal black family retainer; the saintly mothers; a smarmy right-wing politician. A massive deus ex machina tidies up potentially troublesome complications. Yet Plain knows how to wring the emotions from her examinations of family dynamics, and her audience will undoubtedly find this latest effort appealing. (May)