Who could have imagined, at this late date, that Anne Frank, the most famous victim of the Holocaust, should require yet another full-scale treatment? After so many documentaries and biographies, after Broadway and Hollywood have done so much to make her the cynosure of the Nazi genocide, what more is there to say?

We know Anne Frank, the young girl who kept a diary, but we do not know the emerging woman who became a mature writer. When Otto Frank first read his daughter's diary the day after returning to the shop where the Gestapo found his hidden family and learned that Anne had perished in Auschwitz, he remarked that the book revealed someone he had never really known. He may have meant only that he was now privy to her private thoughts. But to Francine Prose, what Otto discovered was a writer.

Anne Frank the artist has been strangely absent from most accounts of her terrible but inspiring ordeal, Prose notes in her book, "Anne Frank: The Book, the Life, the Afterlife." The enormity of the historical event that overwhelmed the Franks and millions of others also served to sequester Anne Frank the stylist, who began to rewrite and polish her diary the day she heard a minister in the Dutch government in exile broadcast from London a call to his fellow citizens to preserve records of their wartime suffering.

Part history, part biography, part literary analysis, Prose's book is a stunning achievement, demonstrating how a precocious Anne Frank meticulously edited and augmented a diary that she conceived of as a work of art. Prose shows how hard Anne worked to foster the seeming artlessness of her diary as the spontaneous overflow of her feelings.

After Prose, it will be impossible to ever read Anne Frank's diary again as an unmediated historical document. But to say that Anne made herself into a character, a narrator as rueful, sarcastic, high-spirited and ambitious as any encountered in the annals of fiction is to take nothing away from her work's veracity. For Anne, at 13, with only two more years to live, had already decided on a career as a writer and was honing all of her considerable talent to make her diary more like herself, not less. Now she stands before us, still that girl, a victim of the Holocaust, but now also a figure who will live not only in history but also in the literature she aspired to create.

Carl Rollyson is a biographer and journalism profes- sor at Baruch College, City University of New York.