Karen Blixen and Julian Barnes both used pseudonyms in their works.
Karen Blixen Baroness Karen Christenze von Blixen-Finecke (née Dinesen; 17 April 1885 – 7 September 1962) was a Danish author who wrote works in Danish and English. She is best known under her pen names Isak Dinesen, used in English-speaking countries, and Tania Blixen, used in German-speaking countries. She also published works using the aliases Osceola and Pierre Andrézel.
Karen Anderson (writer) Karen Kruse Anderson ( ; born September 16, 1932) is the widow and sometime co-author of Poul Anderson and mother-in-law of writer Greg Bear.