Some years ago in Kulen Vakuf, a small rural community on the border between Croatia and Bosnia and Herzegovina, neighbor set upon neighbor, and in several bloody weeks, roughly 2,000 men, women, and children were slaughtered in barbaric fashion. The year was 1941—although readers might have assumed a date five decades later. Bergholz, a historian, stumbled across a blue folder in a Sarajevo archive containing some startling details about the episode and set out on a long quest to piece the whole story together. Croatian militias began the violence; Serbian and Muslim insurgents responded. But the bloodletting was not simply an explosion of long-simmering ethnic hostilities; neither was the violence ginned up by scheming politicians. Putting this beastly case under the microscope, Bergholz probes the role that ethnic identity played. He discovers that strong ethnic identification was often a product of violence rather than a source; that ethnic identities were shifting before, during, and long after the nightmare; and that the rigid ways in which people tend to think about ethnicity in cases like this misleads more than illuminates.