This week 49 years ago NBC aired “Arena” on July 7, 1967,
for its encore broadcast.

This was producer Gene Coon’s first original script for Star Trek.   
NBC Broadcast Standards (the censors) had the usual concerns.   Jean Messerschmidt to Gene Coon wrote:
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Bobby Clark rehearsing a scene at Vasquez Rocks. Photo courtesy of Bobby Clark and from These Are the Voyages, TOS: Season One.
Page 1: Please keep to a minimum the number of bodies seen in the destroyed area.

Page 2: Caution on the makeup used on the wounded Lt. Harold [the survivor of the alien attack], so that his injuries are not unduly alarming.

Page 3: Caution on the death by ray of the Security Guard, so that his disintegration is not grotesque.

Page 15: I assume Dr. McCoy will be using your air-hiss device for the injection; if the needle-type is used, please do not show this on camera.

Page 28: Please use restraint when filming the results of the sudden stop [of the Enterprise] so that the action of being thrown to the floor and the pain is not unnecessarily alarming.

Page 32: Please make sure there is nothing offensive in the Gorn’s appearance.

Page 46: I realize the necessity of establishing that the spear cannot penetrate the Gorn’s hide, but please be especially cautious when filming this sequence.
    The body count was reduced; the radiation burns on Lt. Harold toned-down; and Kirk’s attempt to penetrate the Gorn’s hide with a spear was struck from the script.
     “Arena” was the first episode to refer to the Earth space alliance as the “Federation,” a contribution from Gene Coon.  The script for the upcoming “A Taste of Armageddon,” having been around for a while and going through various revisions by Coon, would be more specific, identifying the alliance as The United Federation of Planets.   “Arena” was also the episode which introduced the photon torpedoes, another Gene Coon invention.
 
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Filming at old fort at Vasquez Rocks. Photo courtesy of Gerold Gurian.
    Watch “Arena” again this week. And then travel back in time and read about its writing and filming and initial reception in the Saturn Award winning book series These Are the Voyages, TOS.