‘The hope is that this body of law will serve as a barrier against the collective wickedness, greed and folly of any nation’, wrote Martha Gellhorn as she watched the twenty – one German leaders being sentenced at Nuremberg. That it singularly failed to do so is only too clear from Elizabeth Neuffer’s very readable study of the Bosnian and Rwandan genocides, The Key to My Neighbour’s House. For Neuffer, it is really more a question of will than of hope – the will, both personal and political, to learn from the horrors of the two conflicts and to secure the justice that is a first step towards a more peaceful future.

Neuffer was a journalist working for the Boston Globe and based in Berlin when she became interested in the question of what turns friends and neighbours into rapists, torturers and executioners. Covering the war in Bosnia, she wrote about the disintegration of a country into a nightmare of nationalist rhetoric and ethnic murder. Unprepared for the barbarities she saw and heard about (she is engagingly ho nest about her own fears and squeamishness), she travelled around with an interpreter, asking awkward and potentially dangerous questions, and forcing herself to watch the exhumations of mass graves, as corpses, ‘gelatinous and oozing’, their hands still wired behind their backs, rose through the mud. Interviewing survivors, prosecutor, soldiers, local mayors and forensic experts, she carefully put together, as well as the evidence allowed , the sequences of killings and mass murders.

From Bosnia, she went on to Rwanda and to much the same process. Tracing the stories of individual families caught up in the massacres, she reconstructed, scene by scene, the unfolding conflict, recreating the days when gangs of Interahamwe youths roamed the streets of Kigali slaughtering Tutsis and moderate Hutus,