The Spartans called it The Trembler; recent history has seen it termed shell shock, combat fatigue, soldier's heart, and Vietnam Syndrome. Whatever the name, post traumatic stress disorder (PTSD) has always been with us. With 20 per cent of the Veterans of the wars in Afghanistan and Iraq exhibiting PTSD symptoms, the United States military has a strong interest in combating the condition. Navy psychiatrist Robert N. McLay has been at the forefront of these efforts. This is his story of using virtual reality to treat Service Members and Veterans with PTSD. As a practicing psychiatrist who works with Veterans and civilians coping with PTSD, McLay had known for years before the September 11, 2001, attacks that effective treatments for the condition were elusive. When active duty called, he met the challenge, becoming the primary investigator on PTSD treatment projects that had Service Members face the ghosts of war in a computer simulator. After using this new form of exposure therapy on the home front, McLay and his team believed they had found a promising way to work with warriors broken by combat, so in 2008 they took it to the front line in Fallujah, Iraq, with the First Marine Expeditionary Force. Several years into the project, McLay recounts openly and with bleak honesty the successes, failures, and limits of virtual reality treatment for PTSD. Filled with poignant firsthand accounts of war and its psychological aftermath, At War with PTSD explains the difficulties of using this specialized technology in the field and discusses such challenges as helping people who refuse to believe in PTSD, including those diagnosed with it. So far, the virtual reality program shows more promise than traditional therapies. And although McLay remains unsure why or how, his experiences hold out hope for those suffering from this devastating disorder.