Trauma Informed Guilt Reduction Therapy (TrIGR) provides mental health professionals with tools for assessing and treating guilt and shame resulting from trauma and moral injury. Guilt and shame are common features in many of the problems trauma survivors experience including posttraumatic stress disorder (PTSD), depression, substance use, and suicidality. This book presents Trauma Informed Guilt Reduction (TrIGR) Therapy, a brief, transdiagnostic psychotherapy designed to reduce guilt and shame. TrIGR offers flexibility in that it can be delivered as an individual or group treatment. Case examples demonstrate how TrIGR can be applied to a range of trauma types including physical assault, sexual abuse, childhood abuse, motor vehicle accidents, and to moral injury from combat and other military-related events. Conceptualization of trauma-related guilt and shame, assessment and treatment, and special applications are covered in-depth.