(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 a 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.