This treatment manual provides mental health professionals with instructions for conducting written exposure therapy (WET) with clients who have posttraumatic stress disorder. Authors Denise Sloan and Brian Marx developed WET in response to a growing demand for an effective PTSD treatment that is easier to implement, more affordable, and has lower dropout rates than other trauma interventions. In their unique approach, the client writes about a single traumatic event, and the therapist focuses on the client's experiences in writing about the trauma, rather than the event itself. Written Exposure Therapy for PTSD contains a scripted protocol for WET along with detailed clinical guidance for conducting each session. Sloan and Marx answer frequently asked questions from clinicians and review real‑life case examples that demonstrate solutions to common issues and challenges that can occur during WET sessions. They also explain how to assess the client before treatment to determine the appropriateness of WET and during treatment to monitor the client's progress. Key background information about PTSD symptoms and WET's theoretical underpinnings are also reviewed.