A single photograph—an exceptionally rare “action shot” documenting the horrific murder of a Jewish family—drives a riveting forensic investigation by a gifted Holocaust scholar.

In 2009, the acclaimed author of Hitler’s Furies was shown a photograph just brought to the United States Holocaust Memorial Museum. The documentation of the Holocaust is vast, but there are virtually no images of a Jewish family at the actual moment of murder, in this case by German officials and Ukrainian collaborators. A Ukrainian shooter’s rifle is inches from a woman’s head, obscured in a cloud of smoke. The woman is bending forward, holding the hand of a barefoot boy. And—only one of the shocking revelations of Wendy Lower’s brilliant ten-year investigation of this image—the photograph reveals the shins of another child, slipping from the woman’s lap.

Wendy Lower’s gripping detective work—in Ukraine, Germany, Slovakia, Israel, and the United States—recovers astonishing layers of detail concerning the open-air massacres in Ukraine. The identities of the victims, of the killers—and, remarkably, of the photographer who openly took the picture, as a secret act of resistance—are dramatically uncovered. Finally, in the hands of this exceptional scholar, a single image unlocks a new understanding of the place of the family unit in the history and aftermath of Nazi genocide.