In this well-intentioned but overly emotional novel, Rosenbaum (whose novel-in-stories Elijah Visible won the 1996 Edgar Lewis Wallant Award) focuses on the lives of Holocaust survivors who cannot achieve peace of mind or soul. The narrative follows Duncan Katz, federal prosecutor and top Nazi hunter, in his obsessive quest for justice and vengeance. Duncan's difficult mother, Mila, survived Auschwitz-Birkenau and, in 1947, fled Warsaw's postwar anti-Semitism by escaping to Germany, where she met and married Duncan's father, Herschel, a survivor of Bergen-Belsen. Later, in Miami Beach, Mila becomes a confidante and collector for notorious Jewish crime boss Meyer Lansky. Duncan, born in 1953, achieves a karate black belt at age nine, stars in high-school football and evolves into a tough, armor-plated prisoner of his own exaggerated fears, nightmares, grief and rage. Like his protagonist, Rosenbaum is the son of Holocaust survivors and grew up in Miami Beach; he writes with empathetic insight into the traumas of those who never escaped their harrowing memories, often unconsciously passing their tortured psyches on to their children. Overzealous Duncan is a time bomb. He destroys a new Mercedes because it was made in Germany; gets fired from the Justice Department after posing as a neo-Nazi in order to tape-record conversations with a former concentration camp guard whom he tries unsuccessfully to deport. Although his moral passion heats up this intense parable, Duncan's overbearing self-absorption dominates the book, and the story turns to creaky melodrama when he discovers that he has a half-brother, Isaac Borowski, whom Mila secretly left behind in Poland. Isaac, who is caretaker of Warsaw's Jewish Cemetery as well as a yoga teacher and Zen disciple, teaches Duncan to let go of his anger, a denouement that feels as contrived as it is cathartic. (Apr.) FYI: Rosenbaum is literary editor of Tikkun.