John Donald Francis Black was a screenwriter, TV producer, and TV director. He is best known for his work on the TV series Star Trek, and its sequel series, Star Trek: The Next Generation during the 1980s.

Black was the associate producer for ten episodes of Star Trek made during the program's first season. Black also wrote the teleplay for and was the associate producer of one of the outstanding early episodes of Star Trek - "The Naked Time". During the 1980s, Black was also given credit for the story for sequel episode, "The Naked Now", in Star Trek: The Next Generation. Black also received shared story-writing credit (with Worley Thorne, who wrote the teleplay) for one more episode in this series, "Justice", under his pseudonym of "Ralph Wills".

Black also wrote for many other TV series, including The Mary Tyler Moore Show, Charlie's Angels, Hawaii Five-O, The Fugitive, Mission: Impossible, and Mannix.

In work for motion pictures, Black co-wrote the movie adaptation of Shaft (1971), along with his co-writer, Ernest Tidyman, who had written the original novel of Shaft. Black also was the screenwriter and executive producer of the detective film Trouble Man (1972), which starred Robert Hooks and whose musical score was written by Marvin Gaye.