The National Diet Library (NDL) is the national library of Japan and among the largest libraries in the world. It was established in 1948 for the purpose of assisting members of the National Diet of Japan (国会, Kokkai) in researching matters of public policy. A major source of public domain works is the Rare Books department, consisting of the former Imperial Library's collection of Japanese language materials from the Edo period (1603–1867) and earlier periods. (Wikipedia)