My wife and I watched City on the Edge of Forever again tonight for the umpteenth time and I caught an error by Harlan Ellison in his story.
Edith Keeler tells McCoy that he is in the year 1930 and she is on the way to a movie with Captain Kirk to see a "Clark Gable" movie. Since I own a run a site for fans of classic films this caught my attention. It so happens that Clark Gable was in many bit parts and most of them not credited but he was not a star in 1930. So Harlan got a little historical fact incorrect. He didn't have any real star billing until he was cast with Greta Garbo in Susan Lennox in late 1931. Oops!