A novel of strong ideas by Prager (a story collection, A Visit From the Footbinder, 1982) that's let down by characters with less- than-riveting credibility. For her 40th birthday, New Yorker Eve, increasingly aware of her fellow-citizens' ``compassion fatigue,'' decides to have the number of a female Holocaust victim, seen in an old photograph, tattooed on her wrist. This memento mori, which Eve compares to the MIA bracelets that she and her friends used to wear, will (she hopes) provoke questions; keep the woman's memory alive; and generally raise consciousness about the Nazis' treatment of women. Eve's action upsets her French lover, Charles, who now reveals that he's actually Jewish and not Catholic as she had supposed. When Eve refuses to have the tattoo removed, Charles moves out. Soon Eve is busy telling stories about Eva, the victim, to anyone who asks, though it's a somewhat select group. This Eva has many incarnations: from a Jewish mother and her baby trying to hide to a Catholic social-worker horrified by the Nazis' treatment of the handicapped and mentally ill. Each incarnation represents some aspect of Nazi policies, which Eve has been reading up on. An accident in which her tattoo is covered by stitches provides the catharsis. Eve finds out to whom the number really belonged; Charles returns; and she finally feels that the experiment was worthwhile. A provocative theme, and the individual Eva stories are good; but Eve and her friends are a very wooden group, whose stagy conversations and banal apercus trivialize the novel's underlying premise.