Leonard Nimoy's father was a barber, who was still operating a barbershop at the time the series became popular. In a mid-1960s interview with 16 Magazine, Nimoy revealed that youngsters often came into the shop asking for a "Mr. Spock" haircut, never realizing that "Mr. Spock's dad" was cutting their hair.
In many interviews, Leonard Nimoy recounted the origin of the Vulcan salute, which he introduced into the show. In one such interview (with The A.V. Club in July 2010), he explained, "the gesture that I introduced into Star Trek, the split-fingered Vulcan salute, we'll call it... that came from an experience - I'm going all the way back to my childhood again - when I was about 8 years old, sitting in the synagogue at high holiday services with my family. There comes a moment in the ceremony when the congregation is blessed by a group of gentlemen known as Kohanim, members of the priestly tribe of the Hebrews. And the blessing is one that we see in the Old and New Testament: "May the Lord bless you and keep you; may the Lord cause His countenance to shine upon you," and so forth. When they give this blessing, you're told not to look! You're supposed to avert your eyes. I peeked, and I saw these guys with their hands stretched out-there were five or six of them, all with their hands stretched out toward the congregation-in that gesture, that split-fingered gesture. Some time later, I learned that the shape that hand creates is a letter in the Hebrew alphabet, the letter shin, which is the first letter in the word Shaddai, which is the name of the Almighty. So the suggestion is that they're using a symbol of God's name with their hands as they bless the congregation."
The character of Uhura was one of the first black regular characters on any series (predating Diahann Carroll's groundbreaking lead role as a young, widowed nurse and single mother in Julia (1968) by two years), and she was especially significant because her character avoided many of the stereotypes that were common among depictions of African Americans in TV at the time. Nichelle Nichols, who played Uhura, has said that Dr. Martin Luther King Jr. himself told her how important it was for her to keep playing the role, since it was so rare to see a positive portrayal of a black character on television. During her interview for the documentary Trekkies (1997), Nichols said that she later heard from at least one viewer for whom King's words had been true as a child: when the actress Whoopi Goldberg (who later went on to star in Star Trek: The Next Generation (1987)) first watched Star Trek (1966), she yelled out, "Momma! There's a black lady on TV, and she ain't no maid!" During a 2011 "Storycorps" interview, Carl McNair, brother of Ronald McNair (the second black person in space and one of the seven astronauts who died in the January 28, 1986, Challenger explosion), recalled the impact that watching "Star Trek" had on Ron: "Now, Star Trek showed the future where there were black folk and white folk working together. I just looked at it as science fiction, 'cause that wasn't going to happen, really. But Ronald saw it as science possibility. He came up during a time when there was Neil Armstrong and all of those guys; so how was a colored boy from South Carolina - wearing glasses, never flew a plane - how was he gonna become an astronaut? But Ron was one who didn't accept societal norms as being his norm, you know? That was for other people. And he got to be aboard his own Starship Enterprise." During the 1970s and '80s, because of her status as the first black person "in space," NASA hired Nichols (during the mid-1970s) to help recruit minority and female astronauts to the program. As a result, NASA Astronaut Group 8 (selected in January 1978) yielded the astronauts she helped sign including Col. Guion Bluford (the first African American in space), Dr. Judith A. Resnik (the first Jewish American person in space), and Dr. Ron McNair. Four of the astronauts (Judith Resnik, Ron McNair, Ellison Onizuka, and Francis Richard "Dick" Scobee) recruited from NASA Group 8 perished in the Space Shuttle Challenger on January 28, 1986 - which later was commemorated during the introduction of Star Trek IV: The Voyage Home (1986).
Shortly after the cancellation of the series, the staff of the marketing department of the NBC TV network confronted the network executives and berated them for canceling Star Trek, the most profitable show on the network in terms of demographic profiling of the ratings. They explained that although the show was never higher than #52 in the general ratings, its audience profile had the largest concentration of viewers of ages 16 to 39, the most sought after television audience for advertisers to reach. In other words, the show, despite the low ratings, had the precise audience advertisers hungered for, which was more than ample justification to consider the show a big success.
Gene Roddenberry originally conceived the Klingons as looking more alien than they do in the series, but budget restriction prevented this, although a very metallic cast to the skin was added to the make-up design in the third season. When the show moved to the big screen, he was finally able to make Klingons look more alien. The resulting continuity break between TOS and all other Star Trek projects was addressed by a humorous comment from Gene Roddenberry that it's the difference between Northern and Southern Klingons. On screen explanations were played with in Star Trek: Deep Space Nine: Trials and Tribble-ations (1996) where it is said that Klingons "do not discuss it with outsiders" but human characters speculate that it was some kind of genetic engineering or a viral mutation. In the fourth and final season of the fifth "Star Trek" series Star Trek: Enterprise (2001) a two-parter comes up with an explanation which turns out to be a combination of those two things.
The uniforms were color coded to show what division of the ship that the crew member was assigned to. The colors were: gold - command (including navigation and weaponry); red - operations (including engineering, security, and ship's services); and blue - sciences (including medicine). It was a few shows into regular series production before red shirts appeared, however, with Uhura and Scott being seen in command gold. In practice, the gold uniforms often appeared apple green, which some have attributed to local interference with television signals. However, the command tunic was actually green, but under most lighting conditions on the set it appeared gold. The true color can be seen in Kirk's special "wrap-around" tunic and to some extent in the special occasion "dress" uniforms, both of which were made out of other materials which reflected the light differently. The uniforms were dry-cleaned, but the velour tended to shrink, so they had to constantly be altered which is why they often looked short on the actors.
When NBC was promoting Star Trek (1966) in magazines, all shots of Spock's pointed eyebrows and ears where airbrushed out of the pictures because NBC thought that no one would watch the show due to Spock's resemblance to the Devil. However, this concern was quickly invalided upon the series' airing with Spock becoming not only one of the most popular characters, but also a sex symbol with young female viewers, an audience reaction no one in the cast or crew anticipated.
George Takei missed nine episodes of the second season because he was away filming The Green Berets (1968). The character of Chekov was created in his absence and Takei's lines were given to Walter Koenig. According to Takei, he was infuriated and was ready to despise Koenig when he returned. But the two ended up becoming close friends.
The series' running "I'm a doctor, not a..." gag originated in the comedy The Kennel Murder Case (1933). The coroner in that film, played by Etienne Girardot, repeatedly claims to be a doctor not a reporter, detective, etc.
According to George Takei, William Shatner had Takei's lines and camera time cut due to Shatner's ego. Shatner denied this and their relationship was contentious ever since. According to episode writer Norman Spinrad, Shatner had it in his contract that he would have more lines than anyone and had some of the other actors' lines cut.
According to producers Herbert F. Solow and Robert H. Justman, William Shatner originally wore 1.5" lifts hidden inside his shoes so that he would appear taller than Leonard Nimoy. Since Shatner was only 5'9", the combination of lifts and the 2" heels of his shoes brought his height to over 6'. It distorted his posture so much so that his stomach stuck out. Understandably, Gene Roddenberry forbid him to wear them, instead opting to dress Nimoy and DeForest Kelley in shoes with only a 1" heel as opposed to Shatner's 2" heel.
Leonard Nimoy's makeup had a faint greenish hue to it, because of his green Vulcan blood. Because the makeup was hand-mixed, the amount of green varied slightly, and in many shots (even close-ups) it's not really visible.
In the original series, the 'arrowhead' badge worn by the crew of the Enterprise was meant to be an insignia for the Enterprise only. If you'll notice on any 'guest' Starfleet character, they all wear different symbols on their uniforms. And Commadores wore a 'starburst' or 'sun' insignia. By the time Star Trek hit the big screen in Star Trek: The Motion Picture (1979), the Arrowhead insignia was adopted as the official Starfleet symbol and has remained so throughout the films and spin-off series, with the exception of Star Trek: Enterprise (2001) which pre-dates the original series.
Kirk never says "Beam me up, Scotty" in any episode, although this misquote is one of pop culture's most popular Star Trek mottoes (used frequently in spoofs), and the title of a memoir-book by William Shatner. Kirk says many similar lines throughout the series - "Scotty, beam us up", "Beam me up", "Scotty, beam me up," "Beam them out of there, Scotty" etcetera etcetera - but never "Beam me up, Scotty." The closest came during the animated spin-off Star Trek: The Animated Series: The Lorelei Signal (1973) when Kirk said "Beam us up, Scotty."
Had the series been renewed for a fourth season, producers planned to bring back Koloth from Star Trek: The Trouble with Tribbles (1967) as a recurring villain. The fourth season would also have seen Roger C. Carmel playing Harry Mudd for the third time, and an introduction of McCoy's daughter Joanna.
Stagehands would pull the turbolift doors on cue with ropes and cables. They would also slide panels by to give the illusion of decks being passed inside the turbolift cars. Some of the more familiar bloopers are that of main actors nonchalantly running into sliding doors that hadn't opened as their characters needed to show full faith in the technology of the Enterprise while stagehands often missed their cues. One of the show's "blooper reels", often shown at Star Trek conventions, includes a full minute of shots of William Shatner walking into various doors and reacting with his favorite profanity (which is not spelled S-H-A-T).
Chekov was added to the show in season two in an attempt to reach out to and expand the show's younger (particularly female) demographics. A discredited story claims that Chekov was created as a Russian after Gene Roddenberry heard about the Soviet newspaper Pravda complaining about the lack of Russian presence on the series, specifically because the Russians were the first to put men in space. There was no such article, as the Soviet Union did not broadcast Star Trek.
Sulu and Uhura didn't have first names in this series. Sulu did get a first name (Hikaru) in source books but it was not spoken on screen until Star Trek VI: The Undiscovered Country (1991). In Season 2 DVD Special Features, Nichelle Nichols reveals that she and Gene Roddenberry accepted the first name "Niota" (also spelled Nyota) for her character, which is a Swahili word meaning "Star". Uhura is a "girly" variant of "Uhuru", Swahili for "freedom". However, the 1968 book, "The Making of Star Trek" by Stephen J. Whitfield and Gene Roddenberry, gave her the first name of Penda. Trek fandom's insistence on ignoring this remains a mystery, as they cite this work on many other points. Niota was finally spoken on screen in the Star Trek (2009) reboot.
Gene Roddenberry created the characters of Uhura & Nurse Chapel especially for Nichelle Nichols and Majel Barrett respectively, both of whom were having affairs with Roddenberry when he conceived the series. Nichols broke off her affair with Roddenberry not long after the series began, though Barrett would eventually marry the series creator. They remained together until his death.
Scotty's full name is Montgomery Scott. The name was improvised on the spot by James Doohan and Gene Roddenberry: 'Scott' because Roddenberry liked Doohan's Scottish brogue, and 'Montgomery' because it's Doohan's middle name.
James Doohan was cast largely for his ability to speak in multiple accents and dialects. Gene Roddenberry had no set nationality or ethnic background in mind for the Enterprise's Chief Engineer. Upon being cast, Doohan tried out many accents for the character, and along with Roddenberry determined that the Scottish accent worked best. Doohan also pointed out the history of great engineers of Scottish origin or descent, most notably Robert Fulton.
An episode was written for comedian Milton Berle to guest star in titled "He Walked Among Us." Berle would have played a sociologist playing God in a primitive society. Berle was a fan of the series and wanted to show his dramatic acting range. But Norman Spinrad's script was rewritten by story editor Gene L. Coon into a comedy. Spinrad was so angry that he wanted the episode scrapped. Gene Roddenberry agreed to scrap the episode after reading the script.
James Doohan (Scotty) lost his right middle finger during World War II. Most of his scenes are shot to hide it. However, it is very noticeable in Star Trek: Catspaw (1967). When Scotty is holding a phaser pistol on Kirk & Spock, only two fingers are holding the butt of the phaser. This is also noticeable in Star Trek: The Trouble with Tribbles (1967), when Kirk's food comes out of the food dispenser filled with tribbles and Scotty walks in carrying a big load of tribbles.
Lloyd Bridges was approached to play Capt. Pike in the original pilot Star Trek: The Cage (1986) but turned it down believing that a science-fiction show would hurt his career. Jeffrey Hunter, who played Capt. Pike, was replaced after his salary demands were deemed to be too high.
According to William Shatner's Star Trek TV memoirs, DeForest Kelley was the first one considered for the role of Spock. Kelley's own claims contradict this, however. He preferred working in Westerns, but Roddenberry talked him into playing a lawyer in a pilot that did not sell, and subsequently approached Kelley for the role of a doctor, in what turned out to be a science-fiction setting. Noting that Hollywood was making fewer and fewer Westerns, the actor accepted.
Kirk's nickname for McCoy "Bones" stems the term Sawbones, which is often used as slang for a surgeon, particularly a Naval or Military Doctor, but also appears in westerns which Gene Roddenberry, DeForest Kelley and other members of the cast and crew "cut their teeth on" prior to Star Trek. The term refers to the process of amputation, a distressingly common response to an inordinate number of problems until very recently. Kirk did call McCoy Sawbones once, in Star Trek: A Piece of the Action (1968). In original scripts for Star Trek: Shore Leave (1966), Sulu called McCoy Sawbones.
Gene Roddenberry originally conceived Spock's skin color to be red, which would have meant extra hours in make-up for Leonard Nimoy. Fortunately for him, an early make-up test showed that the red color merely appeared as black on black-and-white televisions. Since most televisions in the '60s were still black-and-white, the idea was dropped.
Many elements of the Spock character were improvised by Leonard Nimoy during production. For instance, the "Vulcan neck pinch" was his suggestion during filming of Star Trek: The Enemy Within (1966) for how Spock could subdue an opponent. The "Vulcan salute" was created during the production of Star Trek: Amok Time (1967) using a version of a traditional Jewish religious hand gesture as a distinctive Vulcan greeting.
The series' opening theme has lyrics that were never used (although they were published in the book "The Making of Star Trek", by Stephen J. Whitfield). They were written by Gene Roddenberry, not so that they would be sung on-screen (which he never intended or even wanted), but so that he could take a co-writer credit and receive a residual payments for the theme's use alongside the theme's composer, Alexander Courage. Roddenberry did this nearly a year after the show was first aired, taking advantage of a contract clause that Courage claimed not to have been aware of. Although Courage never took the matter to court, he expressed resentment on numerous occasions to the way Roddenberry "swindled" 50% of the popular theme's royalties from him. Roddenberry's response was, "Hey, I have to get some money somewhere. I'm sure not going to get it out of the profits of Star Trek." After the first season of Star Trek, the two never worked together again - although the music has been used in various forms in many of the spin-off projects.
In several episodes, prop beverage bottles were modified from existing alcohol bottles. Aldeberan Whiskey bottles were Cuervo Gold 1800 Tequila bottles. Bottles used for Saurian Brandy were George Dickel Tennessee Sour Mash Whiskey carafes.
According to the Hollywood Entertainment Museum, as of fall 2003 only a few pieces of the original 1960s bridge survive. The museum, on Hollywood Blvd., incorporates two original turboshaft doors into its Star Trek display, while a Los Angeles bookstore reportedly owns the original captain's chair.
Martin Landau was originally offered the role of Commander Spock. Leonard Nimoy had appeared on The Lieutenant (1963), an earlier series produced by Gene Roddenberry, who at the time thought that the actor would be well cast as an alien (when he ran out of choices). Nimoy inspired the creation of the character. Shortly after Star Trek (1966)'s cancellation, he took over the role of disguise-expert on Mission: Impossible (1966) when Landau left that show. Mission: Impossible was also filmed on the same lot, therefore when "Star Trek" ended, Nimoy merely went next door to go to his new job. Also Landau would go on to star in another science fiction space exploration TV series, Space: 1999 (1975), whose last season was produced by Fred Freiberger, who also produced Star Treks final Season.
Grace Lee Whitney was supposed to be the lead female character, hence her prominent role as Yeoman Janice Rand in the first season. However, the producers let go of the character after the first of half of the first season, much to the fans' regret. Whitney, however was asked back for most of the Star Trek movies, reprising her role as Janice.
Stardates are used throughout the series to give the audience an unrealistic look at the time-frame in which the series occurred. However, NBC paid no attention to the producers' intents when deciding on airing order, so the dates were not heard in numerical sequence.
The Romulans were created by Paul Schneider, who said "it was a matter of developing a good Romanesque set of admirable antagonists ... an extension of the Roman civilization to the point of space travel".
Notable for being the first scripted American TV show to display a kiss between black and white races, William Shatner (Kirk) and Nichelle Nichols (Uhura), in Star Trek: Plato's Stepchildren (1968) broadcast 22 November 1968 to considerable controversy. Though the series was well known for its social commentary, Nichols later claimed that more letters were received about that kiss than anything else during the show's run.
In many episodes, alien art work and wall hangings were in reality discarded protective Styrofoam shipping box liners from tape recorders used by fellow Desilu/Paramount show Mission: Impossible (1966), spray painted various colors and arranged into various combined forms.
The images displayed during the end credits of the show tended to follow a specific format. The first image was either an external shot of the Enterprise in space or in orbit of a planet (Seasons 1 and 2) or a shot of the Melkotian head from Star Trek: Spectre of the Gun (1968) (Season 3). The second image was often a specific scene from that particular episode aired, while the rest of the images up until the final one were various images from random episodes. And finally the final image at the end of the credits would be either a shot of the Orion slave girl (from Star Trek: The Cage (1986)) during Season 1, a shot of Big Balok (from Star Trek: The Corbomite Maneuver (1966)) during Season 2, and a simple space shot for Season 3. Also worth mentioning is that the Opening and Closing credits text for Seasons 1 and 2 were yellow, while the text for Season 3 was light blue.
The story that the USS Enterprise's registry number "NCC-1701" was derived from Walter M. Jefferies' antique Waco biplane (FAA registration NC17704) is mostly apocryphal. According to Jefferies himself, the Star Fleet "NCC" was a mix of the original international codes "NC" for United States commercial vehicles and "CC CC" for Russian vehicles. The "1701" was selected for visual clarity, with "17" representing the seventeenth basic Federation ship design, and "01" marking Enterprise as the first commissioned vessel of that design. Interestingly, there was once in fact a Waco YKS biplane registered with the FAA as NC17701.
During the second season there were rumors that the series was to be canceled. A group of science fiction fans, led by Bjo Trimble, organized a letter writing campaign to NBC, begging that the show be renewed for a third season. This campaign was so successful, inundating the offices of NBC with thousands of letters that the series was not only renewed, but voice-over announcements were made over the credits of several episodes of the summer reruns of the show, thanking the viewers for their support of the show and promising that it would return for a third season in the fall.
According to his character biography in the series Writers Guide, McCoy was divorced and had a college aged daughter named Joanna. None of this was mentioned in any episode, though there were a couple of unsuccessful attempts to feature an appearance by Joanna. The character of Irina (Mary Linda Rapelye) in Star Trek: The Way to Eden (1969) was originally to have been Joanna. Joanna would be mentioned in the animated series, and also depicted or referred to in non-canonical Star Trek novels and comics.
George Takei claimed in 2014 that his homosexuality was a guarded secret amongst the cast. Nevertheless he privately pitched to Gene Roddenberry a story idea in which homosexuality would be allegorically depicted by an alien race the crew encounters. Takei claimed that Roddenberry liked the idea, but reluctantly decided it would be too controversial.
The Enterprise is a Constitution-class ship, The space shuttle Enterprise, which was named for her after a fan lobbying campaign of NASA, was originally supposed to be named Constitution. Further, Enterprise NCC-1701 was named for the aircraft carrier Enterprise CVN-65, which along with the "Old Ironsides" USS Constitution was one of the longest-serving warships in the US Navy.
Star Trek: Shore Leave (1966) has the only scene in which the U.S.S. Enterprise is seen orbiting a planet from right to left. The U.S.S. Enterprise also does this briefly in the parallel universe, in the pre-credits sequence of Star Trek: Mirror, Mirror (1967), but by the beginning of Act I, it is again orbiting from left to right.
According to the DVD commentary, many of the sets used for the series were built with easily removable wall panels designed to allow for easy camera placement and easy redressing of the sets for other uses.
As the first season progressed, producers feared that Leonard Nimoy would eventually quit the series. As a result they put together a list of actors to consider for recasting the role of Spock should Nimoy have left. Among the actors considered was Mark Lenard who would eventually be cast as Spock's Father Sarek.
Gene Roddenberry originally envisioned the Enterprise as one of only about twelve to fifteen starships comprising the Federation Starfleet due to the incredible cost in time and resources in building such vessels. This accounts for the Enterprise constantly encountering new or relatively unknown planets and aliens, as well as being the only ship "in range" when some crisis would break out. This idea was gradually dropped with the advent of the films and especially later, with Star Trek: The Next Generation (1987) by which time the Enterprise-D has become the flagship of an entire armada of ships patrolling the galaxy.
Three of the main cast members were the children or grandchildren of Russian-Jewish immigrants: Leonard Nimoy's parents came to North America from The Ukraine, as did William Shatner's grandparents, while Walter Koenig's parents were from Lithuania.
Captain Kirk's birthplace was established to be the state of Iowa, according to Gene Roddenberry in his book "The Making of Star Trek". Although an exact city was never established throughout the series, in 1985 the town of Riverside, Iowa officially proclaimed itself to be the "Future Birthplace of James T. Kirk". Steve Miller, a member of the Riverside City Council who had read Roddenberry's book, suggested to the council that Riverside should proclaim itself to be the future birthplace of Kirk. Miller's motion passed unanimously and the council later wrote to Roddenberry for his permission to be designated as the official birthplace of Kirk, to which Roddenberry agreed. The town is home to many Star Trek-related attractions, events and displays, including a replica of the USS Enterprise (named the USS Riverside), as well as plays host to the annual Riverside Trek Festival.
Each starship and starbase had its own insignia, which was worn on the left breast of the uniform. The Enterprise's insignia was the now well known arrowhead shape. The boomerang shape from the side of the ship was the starfleet command insignia.
There are contradictory indicators as to just how far into the future the series is set. A calendar year for the adventures of the Enterprise crew is never given in any episode, and Gene Roddenberry said the series could have taken place anywhere from the 21st to the 31st Centuries. However, in Star Trek: Tomorrow Is Yesterday (1967), which involves a time-trip to Earth in the 1960s, Kirk is arrested by security at Omaha Air Force Base. When an officer threatens to lock him up for two hundred years if he does not explain who he is and why he is there, Kirk mutters, "That ought to be just about right." Stronger is Star Trek: Space Seed (1967), where a ship filled with people in suspended animation capsules is dated to the 1990s. When the first person revived asks "How long?" a few minutes later, the response is, "We estimate two centuries." An advance print ad for Star Trek: The Motion Picture (1979) had a blurb across the top that began, "In the 23rd Century...," leading fans to protest on the basis of those two original series statements. The ad was soon changed to bear a non-time specific blurb, but "Trekkies" refused to acknowledge the fact that "23rd century" was an error. In Star Trek II: The Wrath of Khan (1982), after the opening credits, the words "In the 23rd Century" appear. By the time of Star Trek: The Next Generation (1987), calendar years for Trek adventures had been established and the official Star Trek Chronology now indicates that the original "Star Trek" TV series takes place between the years 2266 and 2269. (Later in Star Trek: Voyager: Q2 (2001) it was said that Kirk's five-year mission ended in 2270.) It wasn't until Star Trek IV: The Voyage Home (1986), that the 23rd century time line is internally established, in a conversation between Kirk and Dr. Gillian Taylor (Catherine Hicks).
CBS initially expressed an interest in picking up the series, but ultimately passed on it since they were already developing another science fiction TV series Lost in Space (1965). CBS would come to own and distribute the series as a result of their corporate connections with Paramount.
There are conflicting reasons as to why Janice Rand was written out of the series after only eight appearances during the first season. Gene Roddenberry has said it was a budgetary move, but others have claimed that as the show progressed her role as the Captain's Woman, or potential loved interest for Kirk became impractical. Other stories have claimed that Grace Lee Whitney was having issues with alcoholism, which was said to be effecting her work on the series. Whitney herself said she may have been let go to keep her quiet over accusations of a network executive having sexually assaulting her. Whitney would later return to reprise her role as Rand, making brief appearances in some of the Star Trek movies, and a guest appearance on Star Trek: Voyager: Flashback (1996).
The Klingons were intended to look slightly Asian in appearance, but the idea was dropped. However, the concept of Klingon's Warrior Class System, and Imperial nature were similar to aspects of some Asian cultures. The Klingons came to be developed as reflecting Soviet Communists in plots paralleling Cold War issues and tensions of the time (with The Federation representing the US and it's allies). The real life changes in the Soviet Union/Russia would subsequently be reflected by The Klingons in the movies and the later Trek series. The Romulans, who were more secretive in nature, and having an uneasy alliance with The Klingons have come to be viewed as reflecting Red China.
Leonard Nimoy received Emmy Award nominations for Best Supporting Actor in a Dramatic Role for each of the show's three seasons. These would be the only Emmy Award nominations in acting categories for any series in the Star Trek franchise.
One of the Starfleet's directives is that it can't let the inhabitants of planets visited learn of their technology. Yet, there are numerous episodes where communicators, phasers, and other sophisticated equipment is left behind.
Largely reflecting their onscreen roles as Kirk and Spock, William Shatner and Leonard Nimoy came to be close friends in real life. However, some of the other cast members, notably James Doohan and George Takei have said they found it difficult to work and deal with William Shatner, resulting in their dislike of him on a personal level as well.
The creation of the the show's "transporters" and concept of beaming off and on the ship was largely out of practicality. Gene Roddenberry was unable to find a way to plausibly show the Enterprise repeatedly landing on and taking off from different locations in almost every episode.
After appearances in each of the first two seasons, a script featuring Harry Mudd was written for the third season. However, Roger C. Carmel was unavailable to reprise the role, and the episode was put aside for use during the show's fourth season (which never occurred due to the show's cancellation). Carmel would return to voice Harry Mudd in the Star Trek: The Animated Series (1973) Animated Series episode Star Trek: The Animated Series: Mudd's Passion (1973). Mudd was also considered for appearances in Star Trek IV: The Voyage Home (1986) and Star Trek: The Next Generation (1987), but those ideas were scrapped due to Carmel's declining health and subsequent death. Mudd would continue to make non-canonical appearances in various Star Trek novels, comic book stories and other non traditional media adaptations.
Of the five Star Trek series, this is the only one to not feature an appearance by or reference to Ferengi, The Borg, Cardassians, Bajorans, Betazoids, Bolians, Yridians, Trill, Benzites, The Breen, El-Aurians, or Nausicaans. (Though the "Q" are not mentioned by name, Trelane from Star Trek: The Squire of Gothos (1967) is retroactively considered to be a Q.)
In the mid 2000's, a competition was held among real life Scottish cities and towns to be declared as Scotty's Official Birthplace (and Home Town). Linthgow made a strong push, claiming direct reference in some of the show's production notes. Aberdeen won out, largely on the basis of a brief line of dialogue from Star Trek: Wolf in the Fold (1967). James Doohan also said he based Scotty's accent on that of someone he knew who had been from Aberdeen.
Most episodes revolve around Kirk, Spock and/or McCoy. Producers often proclaimed intentions to feature stories focusing on the supporting characters. While Scotty achieved greater prominence in some episodes as the show went on, promised episodes centering around Sulu, Chekov or Uhura never materialized.