Mary Black
Mary Black (née Stowell) worked on  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.

She passed away in  in Woodland Hills, California.

External link 
 at StarTrek.com

Star Trek reference authors
Personal assistants