(written from a Production point of view)
Mary Black (née Stowell) worked on Star Trek: The Original Series as a secretary for John D.F. Black, a writer and Executive Producer on the series (and Mary's future husband). Mary functioned as an executive assistant to John and typed and analyzed show material as it came in to the studio.
Mary and her husband co-wrote and were the subject of several columns in Star Trek: The Magazine between 2001 and 2002.