Star Trek: Deep Space Nine Extended Viewing (part 1)

NOTE: This is still a work in progress. It will be periodically updated.

A lot of science-fiction series these days have extra content like movies or webisodes that lead new viewers to ask what an appropriate viewing order is. Sometimes this leads to debate among fans when movies or specials involve potential spoilers, or just the question of whether to watch them chronologically or in the order they aired (if these differ). While Star Trek: Deep Space Nine has no official extra content (novels, video games and comic books are not considered canon, even though a few are debated), it is also part of the larger Star Trek universe and more than any of the other series draws on all of them for its continuity.

Unlike Star Trek: The Next Generation, which was created by Gene Roddenberry as a follow-up to his original and a refinement of his vision, DS9 is a true spin-off. There were a few times that Next Generation would reference the original series, but these were few and far between (most specifically the episodes "The Naked Now" and "Relics"). DS9 on the other hand co-exists with TNG in the same era. Both series shared characters, alien races and locales. The DS9 pilot even has a sort of "torch-passing" quality and ends with Captain Picard and Commander Sisko shaking hands. This is not surprising since a number of former Next Generation writers went on to Deep Space Nine. As some of them were fans of the original series as well, certain facets of that series made their way onto DS9, even to the point of doing sequels to classic episodes.

It is generally possible for a new viewer to watch Deep Space Nine without having seen any other Trek. It's a unique series and may appeal to non-Trek viewers who do like other series like Babylon 5. It is also a far more serialized show than any of the others (with the exception of Enterprise in its later seasons). While the writers do try to explain outside elements for the uninitiated, I've compiled here a list of episodes to consult from the other Trek series where they relate to DS9 episodes, especially in cases where a DS9 story is a direct follow-up to an episode from a previous series. To begin with, I will note a DS9 episode followed by the other Trek stories I feel should be viewed before it. I will try to keep this specific to the needs of a DS9 viewer; there are many little threads that can connect throughout the many series. I know that Buck Bokai was first mentioned in "The Big Goodbye", but not knowing that doesn't really effect an episode like "If Wishes Were Horses".

A follow-up post will include a full chronological viewing order.

Useful abbreviations:
TOS -- The Original Series ("Classic Trek")
TAS -- the animated series
TNG -- Star Trek: The Next Generation
VOY -- Star Trek: Voyager
ENT -- Enterprise (later known as Star Trek: Enterprise)

DEEP SPACE NINE EPISODES AND THEIR CONNECTIONS:
"Emissary" -- First and foremost, the story is established with a flashback to "The Best of Both Worlds" (TNG). This is essential to establishing the tension between Picard and Sisko. It's briefly touched on with an opening text crawl, but if you can see the original episode, you should. "Best of Both Worlds" is helped by having backstory on the Borg, who were introduced in "Q Who" (TNG), but also hinted at in "The Neutral Zone" (TNG). The latter is not really essential, but a mystery element is explained and referenced in the later two episodes.

The Bajorans and their backstory with the Cardassians are introduced in "Ensign Ro" (TNG). You'll find that terminology and pronunciation tend to differ in these early episodes. The character of Ensign Ro Laren was originally to be the Major Kira role on DS9, and you may note the similarites in the pilot.

The Cardassians were introduced in "The Wounded" (TNG). That episode also told how O'Brien served during the Cardassian War, which is mentioned in later episodes. O'Brien himself appears in numerous TNG episodes, generally as a transporter chief. He actually first appears in the TNG pilot, "Encounter at Farpoint", though is not named until later. His wife Keiko was introduced in "Data's Day" (TNG) when they were married, and his daughter Molly was born in "Disaster", delivered by Worf. This event is the set-up for a minor joke toward the middle of the show's run.

The Trill were first introduced as a race in "The Host" (TNG). However, DS9 treats them very differently, contradicting much of what was previously established. It is therefore unnecessary for a novice viewer to see this episode and might prove confusing.

The less said about the early Ferengi episodes the better, but they first appear in "The Last Outpost" (TNG). Definitely not required viewing.

"Past Prologue" -- the Duras sisters make an appearance. Their backstory is part of the Klingon political arc that played over several seasons of TNG, which grew and expanded over the course of DS9. The sisters, Lursa and B'Etor first appear in the two-part "Redemption" (TNG), which is a follow-up to both "Sins of the Father" (TNG) and "Reunion" (TNG). "Redemption" also introduced a new character born from a complex backstory begun in "Yesterday's Enterprise" (TNG), which also references "Skin of Evil" (TNG).

"Q-Less" -- a sequel to "Qpid" (TNG), which itself was a sequel to two episodes, "Captain's Holiday" (TNG) and "Deja Q" (TNG). "Deja Q" follows up on the events of "Q Who", but "Q Who" also references the two prior appearances of Q, which are less important. Q first appeared in "Encounter at Farpoint", and recurred in "Hide and Q". The latter is is only worth watching if you care to understand the events referred to early in "Q Who". It should also be mentioned that "Q Who" slightly retcons the ending of "Hide and Q".

"Rivals" -- no strong connections in this episode, however the primary villain is described as an El Aurian, the same race as Guinan on TNG. The backstory of the El Aurian people as refugees from the Borg (referenced in this episode) is established in "Q Who". El Aurian refugees also play an important part in the movie Star Trek Generations.

"Blood Oath" -- The three Klingons in this episode are all from classic Trek episodes. While none of these are necessary viewing before this particular episode, they may be of interest. Kor appeared in "Errand of Mercy", the first episode to depict Klingons, and the animated episode "The Time Trap". Koloth was featured in "The Trouble With Tribbles" as well as the animated sequel "More Tribbles, More Troubles", and Kang appeared in "The Day of the Dove". Kor appears in several subsequent DS9 episodes.

"The Maquis" parts I and II -- The politics behind the Maquis story arc begin in the TNG episode "Journey's End". That episode was a send-off for Wesley Crusher, and in that regard is a follow-up to "Where No One Has Gone Before" (TNG). If you only care about the set-up for the Maquis, then "Where No One..." is not necessary viewing. But watching it will help make the ending for Wesley make a bit more sense. As the story here is about Wesley leaving Starfleet Academy, you may also want to watch "Final Mission" (TNG) in which Wesley leaves the Enterprise for the Academy, though this is also unnecessary for understanding DS9.

The Maquis will play a significant role on DS9 and in the set-up for Voyager. Mention is made in "The Maquis, Part I" of ships disappearing in the Badlands; this may refer to events we will learn about in the  Voyager pilot.

"Crossover" -- A direct sequel to the classic episode "Mirror, Mirror" which involved a parallel universe. DS9 features the Mirror Universe in several more episodes. The prequel series Enterprise also had a two-part story set in this universe, which ended up in its own way being a sequel to the TOS episode "The Tholian Web". Only "Mirror, Mirror" is required viewing, but fans of this universe may want to check out the other episodes. Bear in mind, it is worthwhile not to watch the ENT episodes until after having seen the movie Star Trek: First Contact; it would spoil that film's ending.

"Tribunal" -- O'Brien's war record as first mentioned in "The Wounded" is brought up again.

"Defiant" -- A follow-up to a story thread from the TNG episode "Second Chances" in which Riker is split in two by a transporter accident. Incidentally, no onscreen explanation is given for the animosity Riker shows toward O'Brien in the DS9 episode.

"Through the Looking Glass" -- The Tuvok character in the mirror universe is from Voyager.

"The Way of the Warrior" -- This episode marks when Worf joins the series. He was a character on Next Generation, and arrives after the destruction of the Enterprise in the movie Star Trek Generations. His relationship with Gowron and some of their history that is discussed comes from the two-part "Redemption". That story is a follow-up to "Yesterday's Enterprise", which also introduced Worf's fondness for prune juice.

Worf mentions both Emperor Kahless and the monastery on Boroth, referencing "Rightful Heir" in which Worf spent some time at the monastery.

Worf's son Alexander first appears in "Reunion", the product of a union in an episode called "The Emissary". He spent some time with Worf's human parents on Earth before joining Worf on the Enterprise for several years, beginning with the episode "New Ground". Worf and O'Brien touch on this briefly in this episode.

"Bar Association" -- the two instances of theft on the Enterprise that Odo cites are the TNG episodes "Rascals" and "A Matter of Time".

The Ferengi practice of oo-mox, mentioned here and in other episodes, is first described in TNG's "Menage à Troi".

"The Muse" -- Lwaxana's story about her daughter Kestra is detailed in the TNG episode "Dark Page".

"To the Death" -- The Iconian gateways, and the skirmish with the Romulans that Worf alludes to, are from the episode "Contagion" in season 2 of TNG.

"Trials and Tribble-ations" -- a sequel to the classic episode "The Trouble With Tribbles". As the DS9 gang actually visit the events of this episode, it's best to watch it first.
The Animated Series did a follow-up episode, "More Tribbles, More Troubles", though this is not essential viewing.
The incident with the Gorn which Sisko references is the episode "Arena" (TOS). The "long story" Worf referred to regarding the different Klingon make-up was finally told on Enterprise in the two-parter "Divergence" and "Affliction". These episode were also something of a follow-up to the Augments trilogy ("Borderland", "Cold Station 12", "The Augments") and deal in some small part with the Eugenics Wars first established in "Space Seed" (TOS).

"Let He Who is Without Sin..." -- The pleasure planet Risa was first introduced in "Captain's Holiday" (TNG). No prior knowledge is essential for this episode though. This is also the first episode since "Heart of Glory" (TNG) to refer to Worf growing up on Gault. Risa made one more appearance in the Enterprise episode "Two Days and Two Nights".

"Doctor Bashir, I Presume" -- Dr. Zimmerman was introduced on Voyager. He is the model for The Doctor on that series. At the time of this airing, Zimmerman had appeared on Voyager in the episodes "Projections" and "The Swarm" and would appear once again in "Life Line".
The new holographic form turns out to be Andy Dick when the EMH Mark II (whether this is meant to be the LMH of this episode is uncertain) was introduced in "Message in a Bottle" (VOY).
The reference to Khan Singh is of course to "Space Seed" (TOS) and it's big-screen follow-up Star Trek II: The Wrath of Khan. The character of Khan also appears in Star Trek Into Darkness. Admiral Bennett is in error when he says that was 200 years ago; he's off by a couple centuries.

OTHER TREK EPISODES WITH TIES TO DEEP SPACE NINE:
For the completist who might want to see all things related to Deep Space Nine, here are a few other connections.

"Birthright" parts 1 and 2 (TNG) -- The Enterprise docks at Deep Space Nine, and part 1 features a guest appearance from Dr. Bashir.

"Firstborn" (TNG) -- Following on the Duras Sisters' appearance in "Past Prologue", the Enterprise contacts Deep Space Nine looking for them. Quark makes an appearance.

"Preemptive Strike" (TNG) -- If you like the Maquis element of the show, you may appreciate this Maquis-centric story. Apart from an appearance by Gul Evek and a passing reference to Deep Space Nine, this episode has no connection to that series. But it does help flesh out the Maquis a bit more.

"Caretaker" (VOY) -- The 2-hour pilot for the Voyager series begins with Maquis characters in the Cardassian  badlands and a cameo from Gul Evek. Voyager herself launches form DS9, and there's a scene at Quark's.

Star Trek: First Contact -- This movie brings Worf back to the Enterprise for its duration after the Defiant is damaged in battle with the Borg.