Gerda Petersen Jordan was one of the few American scholars to study Hans Henny Jahnn. I recently contacted her school and discovered that she passed away a few years ago.
Professor Jordan left us a great gift in her translation of Jahnn's Thirteen Uncanny Stories (Peter Lang, 1984) and her 21 page introduction to Jahnn and his work included in this volume.
Bio from the back cover of her Jahnn translation:
Gerda Jordan was born in Hamburg in 1927 and emigrated to the United States after World War II. She studied literature and linguistics at the University of South Carolina where she received her Ph.D. in 1971 in Comparative Literature. She is now Associate Professor of German and Comparative Literature at the University of South Carolina, specializing in 19th-century literature.
She co-translated Johann Beer's Summer Tales. This early German novel was published in 1682.