Current cases of Posttraumatic Stress Disorder (PTSD) worldwide are estimated to be in the tens of millions. If this estimate is valid, PTSD is the world’s second most common mental disorder. PTSD is associated with severe distress, high levels of chronicity, co-morbidity and disability, and significant economic (productivity) consequences. Very high prevalence rates of PTSD are reported for post-conflict countries for example, 37% for Algeria’s general population and 28% in Cambodia. Still higher rates of PTSD are reported in Western Europe, North America and Australia for people claiming refugee status. These epidemiological findings are recent developments, for PTSD only entered the psychiatric nosology in 1980. Since then, the character of PTSD has been further defined to include subvarieties, notably, ‘partial PTSD’, ‘vicarious PTSD’ and ‘collective trauma’. PTSD has also attracted the attention of several critics, who have questioned its underlying epistemology and actual clinical significance. In this paper, I review these various claims and critiques. I approach PTSD from three perspectives: human memory (the ‘motor’ that is said to drive The PTSD syndrome), social relations (PTSD comprises a language of entitlement as well as a disorder) and history (not only the history of PTSD, but PTSD as a medium for composing history).‬