Born Evangeline Ensley in 1907 in Indianapolis, Indiana, she published the first volumes of her Mabinogion trilogy, based on the book of Welsh legends, The Virgin and the Swine, in 1936. It was published in 1970 as The Island of the Mighty and followed by The Children of Llyr, The Song of Rhiannon, and The Prince of Annwn. Known as a fantasy writer with a large following in America and Europe, she also published Witch House (1945), The Cross and the Sword (1956), and Son of Darkness (1957). She moved to Tucson in 1940 where she passed in 1996.
Collection consists of biographical clippings, correspondence, and manuscripts. Correspondence is divided into two categories, general and John C. Powys, Welsh novelist, essayist and poet.