This issue of the PTSD Research Quarterly is the third in an occasional series on the epidemiology of trauma and PTSD around the world, following previous issues on Latin America (Fall 2009) and the Middle East (Fall 2010). Whereas published reviews of epidemiologic studies focus primarily on North America, this series aims to highlight other relevant bodies of work. In this issue, I consider research conducted in a specific country, Japan, rather than in a region of the world.