This field guide is designed to provide USAID field staff with practical guidance on a range of issues related to preventing and responding to mass atrocities. ● Mass atrocities are large-scale and deliberate attacks on civilians. ● Mass atrocities vary in context, perpetrators, targeted groups, means, and motives. ● Mass atrocities and armed conflict are overlapping but distinct. Actions to prevent the outbreak of armed conflict should be a major part of an atrocity prevention strategy