The episode {Assignment: Earth} was written to introduce a hoped-for spin-off series that never materialized. It would have featured Robert LansingRobert Lansing as Gary Seven, Victoria VetriVictoria Vetri as Isis, and Teri GarrTeri Garr as Roberta Lincoln. In the new series, the intrepid three would have worked to make sure humanity achieved the destiny glimpsed via the Trek characters and Seven's mysterious extraterrestrial information. While the series never made it to television, it has become a comic book series.
{A Piece Of The Action} is the only episode in which the Enterprise phasers are used to stun.
In only one episode ({Mirror, Mirror}) does Scotty address Kirk as "Jim".
After viewing the popularity of characters such as Robin on the [Batman] series and shows like [The Monkees], the producers decided to introduce Ensign Pavel Chekov in the second season in order to attract more teenage viewers, especially girls, to the show. Walter KoenigWalter Koenig was selected due to his resemblance to [?] Davy Jones.
In {Catspaw}, the alien voices of the revealed forms of Sylvia and Korob are actually the sounds made by newly-hatched alligators calling for their mother.
The slanting crawlway that leads up to the warp-drive nacelles is referred to as a "Jefferies tube." This is a reference to art director [?] Walter M. Jefferies.
The series' opening credits has lyrics that were never used (although they were published in the book The Making of Star Trek, by [?] Stephen A. Whitfield). They were written by Gene RoddenberryGene Roddenberry so that he would receive a residual for the theme's use alongside the theme's composer, Alexander CourageAlexander Courage.
Ranked #1 in [TV Guide]'s list of the "25 Top Cult Shows Ever!" (30 May 2004 issue).
[{Shore Leave}] is the only episode in which the U.S.S. Enterprise is seen orbiting a planet from right to left. The I.S.S. Enterprise also does this briefly in the parallel universe, in the teaser to {Mirror, Mirror}, but by the beginning of Act I, it is again orbiting from left to right.
In the episode {Assignment: Earth}, Spock mentions all the events that would happen the week of 1968 that they arrived in. Among the events he mentioned was an important political assassination. A few days after that episode aired, [?] Martin Luther King Jr. was shot and killed in Memphis, Tennessee.
