Six television series make up the bulk of the Star Trek mythos: The Original Series, The Animated Series, The Next Generation, Deep Space Nine, Voyager, and Enterprise. All the different versions in total amount to 726 Star Trek episodes have been produced across the 30 seasons of the TV series, holding the record of second most episodes produced in all spin-offs collectively (Doctor Who holding first place with currently 880 episodes (as of September 1, 2012)).
The Original Series (1966–1969)
Star Trek, also known as "TOS" or The Original Series, debuted in the United States on NBC on September 8, 1966. The show tells the tale of the crew of the starship Enterprise and its five-year mission "to boldly go where no man has gone before." The original 1966–1969 television series featured William Shatner as Captain James T. Kirk, Leonard Nimoy as Spock, DeForest Kelley as Dr. Leonard "Bones" McCoy, James Doohan as Montgomery "Scotty" Scott, Nichelle Nichols as Uhura, George Takei as Hikaru Sulu, and Walter Koenig as Pavel Chekov. During the series' original run, it earned several nominations for the Hugo Award for Best Dramatic Presentation and won twice: for the two-parter "The Menagerie" and the Harlan Ellison-written episode "The City on the Edge of Forever". The show's creator, Gene Roddenberry, was not involved in the show during its third and final year of production due to a dispute with NBC, with the exception of having co-authored two episodes produced that year.
The Next Generation (1987–1994)
Star Trek: The Next Generation, also known as "TNG", takes place about a century after The Original Series (2364–2370). It features a new starship, the Enterprise-D, and a new crew led by Captain Jean-Luc Picard (Patrick Stewart) and Commander William Riker (Jonathan Frakes). The series introduced alien races new to the Federation as crewmembers, including Deanna Troi, a half-Betazoid counselor played by Marina Sirtis and Worf as the first Klingon officer in Starfleet, played by Michael Dorn. It also featured Gates McFadden as Dr. Beverly Crusher, LeVar Burton as chief engineer Geordi La Forge, the android Data portrayed by Brent Spiner, and Dr. Crusher's son Wesley Crusher played by Wil Wheaton. The show premiered on September 28, 1987, and ran for seven seasons, ending on May 23, 1994. It had the highest ratings of any of the Star Trek series and became the #1 syndicated show during the last few years of its original run, allowing it to act as a springboard for ideas in other series. Many relationships and races introduced in TNG became the basis of episodes in Deep Space 9 and Voyager. It earned an Emmy nomination for Best Dramatic Series during its final season. It also received a Peabody Award for Outstanding Television Programming for the episode "The Big Goodbye".
Deep Space Nine (1993–1999)
Star Trek: Deep Space Nine, also known as "DS9", takes place during the last years and the immediate post-years of The Next Generation (2369–2375) and aired for seven seasons, debuting the week of January 3, 1993. Like Star Trek: The Next Generation, it aired in syndication in the United States and Canada. Unlike the other Star Trek series, DS9 takes place primarily on a space station rather than aboard a starship.
The show begins after the brutal Cardassian occupation of the planet Bajor. The liberated Bajoran people ask the United Federation of Planets to help run a Cardassian built space station, Deep Space Nine, outside of Bajor. After the Federation takes control of the station, the protagonists of the show discover a uniquely stable wormhole that provides immediate access to the distant Gamma Quadrant making Bajor and the station one of the most strategically important locations in the galaxy. The show chronicles the events of the station's crew, led by Commander (later Captain) Benjamin Sisko, played by Avery Brooks, and Major (later Colonel) Kira Nerys, played by Nana Visitor. Recurring plot elements include the repercussions of the Cardassian occupation of Bajor, Sisko's spiritual role for the Bajorans as the Emissary of the Prophets, and in later seasons a war with the Dominion.
Deep Space Nine stands apart from earlier Trek series for its lengthy serialized storytelling, conflict within the crew, and religious themes—all elements that critics and audiences praised but Roddenberry forbade in the original series and The Next Generation. Nevertheless, he was informed before his death of DS9, making this the last Star Trek series connected to Gene Roddenberry.
Star Trek: Voyager, also known as "VOY", ran for seven seasons, airing from January 16, 1995, to May 23, 2001, launching a new Paramount-owned television network UPN. It features Kate Mulgrew as Captain Kathryn Janeway, the first female commanding officer in a leading role of a Star Trek series, and Commander Chakotay, played by Robert Beltran. Voyager takes place at about the same time as Deep Space Nine and the years following that show's end (2371–2378). The premiere episode has the USS Voyager and its crew pursue a Maquis ship (crewed by Federation rebels). Both ships become stranded in the Delta Quadrant about 70,000 light years from Earth. Faced with a 75-year voyage to Earth, the crew must learn to work together and overcome challenges on the long and perilous journey home while also seeking ingenious ways to shorten the return voyage. Like Deep Space Nine, early seasons of Voyager feature greater conflict between its crewmembers than seen in later episodes. Such conflict often arises from friction between "by-the-book" Starfleet crew and rebellious Maquis fugitives forced by circumstance to work together on the same ship. Eventually, though, they settle their differences, after which the overall tone becomes more reminiscent of The Original Series. Voyager, isolated from many of the familiar aspects and races of the Star Trek franchise, faces new races and original plot lines not possible when in a show that takes place in the other Star Trek series. Later seasons, however, brought an influx of characters and races from prior shows, such as the Borg, Q, the Ferengi, Romulans, Klingons, Cardassians as well as cast members of The Next Generation.
Star Trek: Enterprise, also known as "ENT", originally titled Enterprise, is a prequel to the original Star Trek series. It aired from September 26, 2001 to May 13, 2005. Enterprise takes place in the 2150s, some 90 years after the events of Zefram Cochrane's first warp flight and about a decade before the founding of the Federation. The show centers on the voyages of Earth's first warp-five capable starship, the Enterprise, commanded by Captain Jonathan Archer (played by Scott Bakula), and the Vulcan Sub-Commander T'Pol, played by Jolene Blalock.
During the show's first two seasons, Enterprise had an episodic structure, like The Original Series, The Next Generation and Voyager. The third season consisted of one arc, "Xindi mission", which had the darker tone and serialized nature of Deep Space 9. Season 4 consisted of several two to three episode mini-arcs. The final season showed the origins of elements seen in earlier series, and it rectified and resolved some core continuity problems between the various Star Trek series. Ratings for Enterprise started strong but declined rapidly. Although critics received the fourth season very well, both fans and the cast reviled the series finale, partly because of the episode's focus on the guest appearance of members of The Next Generation cast. The cancellation of Enterprise ended an 18-year run of back-to-back new Star Trek shows beginning with The Next Generation in 1987.