Few writers have stared so unflinchingly into the face of violence as has Philip Caputo. In his Pulitzer Prize-winning book "Rumor of War," and in "Horn of Africa" and "Indian Country," he tried to make sense of war and atrocities. Now, in the novel Equation for Evil (HarperCollins), he probes the psyche of a mass murderer. A lone gunman dressed in Army combat fatigues opens fire on a busload of Asian American children in San Joaquin, California. With cruel efficiency, he kills 14 and wounds four more, and then commits suicide. In the wake of this massacre, the search begins for some way to understand such a senseless act. Justice Department Special Agent Gabriel Chin joins forces with forensic psychiatrist Leander Heartwood to perform a psychological autopsy on the gunman, Duane Boggs. Their investigation takes them back through Boggs' life and his association with an underground racist group called WAR, the White Aryan Resistance. In a surprising development, they find indications that Boggs did not act alone. Equation for Evil is a terrifying look into the modern heart of darkness.