Abstract: Though most agencies have trained and equipped their officers for immediate response to mass casualties, few have prepared their personnel for the psychological fallout. Tragic events can have a profound effect on first responders, who may suffer emotional distress that lingers long afterward. To help the Newtown (Connecticut) Police Department cope with the murder of 26 people, including 20 children, at Sandy Hook Elementary School, the COPS Office reached out to the National Alliance on Mental Illness (NAMI) to provide guidance. Preparing for the Unimaginable is the result of NAMI's work with Newtown's police chief, Michael Kehoe. This unique publication offers expert advice and practical tips for helping officers to heal emotionally, managing the public, dealing with the media, building relationships with other first responder agencies, and much more. But what makes this handbook especially helpful are the personal contributions of four police chiefs and numerous officers who have lived through incidents such as these and shared their experiences.