Author. Rainey’s correspondence files (1902–1954); newspaper clippings (1910–1954), including reviews of Rainey’s books and other articles relating to the Rainey family and Oklahoma history; diaries and notebooks (1880–1940); pamphlets and booklets (1903–1968); and manuscripts by Rainey and others relating to Oklahoma and U.S. history; certificates (1905–1937) issued to Rainey; a copy of a patent (1904) for an adding machine; and a billfold (circa 1890) carried by Rainey during the Oklahoma land run of 1893.