For Goudge, a writer who's dedicated most of her career to teen romances, this hard-cover debut represents a kind of authorial coming-of-age. It is the stuff that mini-series are made of (indeed, ABC plans one), at worst patently--and, on occasion, clumsily--manipulative, at best warmly down-to-earth, † la Susan Isaacs. How better for a commercial soap to begin than with a baby switch during a maternity-ward fire? The swap's carried out by distraught Sylvie Rosenthal, whose own daughter came out looking far too like her lover, a Greek gardener named Nikos. So her real girl grows up Rose Santini in an Italian section of Brooklyn, raised by the vicious Santini matriarch, Nonnie. Rose finds solace in her friendship with schoolmate Brian McClanahan, who becomes her fiancÇ just before shipping off to Vietnam. Meanwhile, back at the Rosenthals, Sylvie brings up Rachel (by blood, a Santini) among Bergdorfs and Bendels; medicine is Rachel's chosen course, via a mangled abortion and a stint at a hospital in Vietnam, where she falls in love with and marries. . .guess which GI? Still, Rose keeps the torch burning for her errant Brian, even when a wonderful lawyer slavers at her feet. And in the end, siblings and loves get sorted out when Rose (now a lawyer herself) defends Rachel against a malpractice charge. Goudge has to struggle to maintain the credibility of her theme--the embracing of difficult, dangerous lies--and seriously mars Rachel's sympathy-quotient in the abortion section. But there's little doubt that she has a knack for this kind of thing, and that with practice, the ranks of the diva women's book writers will open unto her.