I researched at The Prange Collection (Maryland University) 13 times for clearing of the Japanese sub-reader publishing after the World War II. I have made a booklist; author, title, date, publisher, for every materials. Sub-reader is, a reference book, a workbook, a guidebook, juvenile literature, self-study book (note). The Prange Collection has too many books, what are not owned by Japanese library. These books are handed in for censord by G2 of GHQ.