Four decades after the USS Enterprise set off on its five-year mission on Sept. 8, 1966 on NBC, the original Star Trek continues to set the bar for compelling television storytelling in the science fantasy genre. Trek's combination of science fiction concepts with solid character-based drama secured it recognition by M.I.T. as one of three seminal U.S. science fiction television series, alongside The Twilight Zone and Babylon 5. Trek creator Gene Roddenberry filled the mid-1960s airwaves with extraordinary tales penned by both skilled television dramatists like D.C. Fontana and Gene Coon as well as famous science fiction scribes like Richard Matheson, Harlan Ellison and Theodore Sturgeon.

In honor of the show's 40th anniversary, here's a list of the seven best-written episodes from the three-year run of the original series-episodes that show, four decades later, what it takes to create a pop culture phenomenon. (Note: Episodes are in order of original airdate.)

"Where No Man Has Gone Before" Written by Samuel A. Peeples
Aired: Sept. 22, 1966
 

Star Trek's second pilot episode (the first, "The Cage," was rejected by network executives) and third to air ("The Man Trap" was the debut show) , came from the pen of prolific television scribe Samuel A. Peeples. Nonetheless it was deeply rooted in one of creator Gene Roddenberry's favorite themes -- that of mankind's power advancing beyond his wisdom. At the edge of our Milky Way galaxy, an energy barrier causes navigator Gary Mitchell (Gary Lockwood) to develop extrasensory capabilities that increase exponentially. Faced with a choice between killing his best friend or bowing to the god-like Mitchell, Captain James Kirk (William Shatner) encounters the first of the series' many no-win scenarios. Deeming the show's initial pilot "too cerebral," NBC executives were won over by Peeples' script, which effortlessly wove complex philosophical ideas, such as man's unbridled potential, together with more traditional action fare: a good ol' fistfight between hero and flawed neo-god.

"The Menagerie" Parts 1 & 2

Written by Gene Roddenberry
Aired: Nov. 17 & 24, 1966

With production of the show falling massively behind, Roddenberry pulled an unbelievable ace out of his sleeve when he penned "The Menagerie," a story that took place entirely on the sets of the preceding episode filmed, "Court-martial," while utilizing abandoned footage from Trek's unaired original pilot, "The Cage." The pilot, concerning a duel of wills between former Enterprise Captain Christopher Pike (Jeffrey Hunter) and the telepathic inhabitants of planet Talos IV, had explored Roddenberry's other pet theme of mankind rebelling against any imprisonment, even a pleasant one. Framing the unused footage within a trial that finds First Officer Spock (Leonard Nimoy) accused of breaking quarantine to return Pike to Talos IV, Roddenberry deployed his earlier story as evidence to the court while using Spock's narration to explain the story's more esoteric aspects. An amazing feat of combing reused footage with production economy, the two-part story not only became a stopgap that kept the series on the air but also picked up a Hugo Award for dramatic writing in the field of science fiction.

"The Devil in the Dark"
Written by Gene (L.) Coon
Aired: March 9, 1967

Written by one of the creators/writers of "The Wild Wild West" T.V. series, and one of the fastest writers in the TV business, "The Devil in the Dark" epitomizes the optimistic outlook of Star Trek when Kirk and company investigate a dangerous creature that is killing the workers at a mining colony. Coupling imaginative science fiction concepts such as silicon-based life with emotional drama that asks the viewer to consider the perspective of the story's antagonist; the episode is only the tip of the iceberg of Coon's contributions to the franchise. Having created the warlike Klingon race, the genetically engineered villain Khan (Ricardo Montalban) -- a character who would return in 1982's Star Trek II: The Wrath of Khan -- and even the Prime Directive (a rule governing the Enterprise crew's dealings with primitive cultures), Coon's work on the series is still best defined by this story, which exhibits the writer's respect for humanity in even the most alien of creatures.

"The City on the Edge of Forever"
Written by Harlan Ellison
Aired: April 6, 1967

Widely regarded as the best episode of the original Trek, Harlan Ellison's story is a work of magical realism that finds Kirk and Spock propelled back to Depression-era New York, where they must ensure that humanitarian Edith Keeler (Joan Collins) is killed in a traffic accident, or else face an alternate future where the Nazis win World War II. The catch? Kirk has fallen hopelessly in love with Keeler. A controversial episode, "The City on the Edge of Forever" was rewritten by D.C. Fontana and the staff , leading Ellison to publish his original WGA Award-winning draft in 1995 along with a lengthy introduction detailing the story's history. Originally set in motion by the actions of a degenerate Enterprise crewman "drug addict" whose one selfless act - saving Keeler - condemns history to a fascist-ruled alternative, the story was revised to highlight the show's emerging third lead, Dr. Leonard "Bones" McCoy (DeForest Kelley), and to appease sensors' and T.V. executives' objections to the controversial subject matter. Despite the differences of opinion regarding the tale's specifics, there can be no doubt that the power of the writer's original concept still resonates today. The as-filmed episode won a second Hugo for the series and entered the pop culture conscience, spawning allusions in work as diverse as the comic strip Foxtrot to the rock group Edith Keeler (Must Die).

"Amok Time"
Written by Theodore Sturgeon
Aired: Sept. 15, 1967

Prolific science fiction author Theodore Sturgeon's second teleplay for Star Trek finds Kirk and McCoy compelled to return  Spock to his home planet of Vulcan, where he must endure an ancient mating ritual or die. Sturgeon's trademark use of sexuality to explore character is front and center in this Season 2 opener, as Spock's intended mate T'Pring (Arlene Martel) demands that Spock kill his captain before he be allowed the coital release he requires. Yet another story that demands sacrifices of the show's heroes and offers no apparent compromise, "Amok Time" was the first glimpse at Vulcan culture -- finally contextualizing Commander Spock in terms of his species. Daringly provocative in terms of late '60s mores, the narrative is even more astonishing in its implicit assertion that an act of extreme violence fulfils the same ends as sexual gratification. Sure, this was following on the heels of the Summer of Love, but it was also 8:30 p.m. Friday night on NBC.

"Journey to Babel"
Written by D.C. Fontana
Aired: Nov. 17, 1967

A political thriller that finds the Enterprise playing host to assorted dignitaries en route to a top secret conference, "Journey to Babel" by series story editor D.C. Fontana manages to spin an engaging murder mystery around an even more compelling family drama. When an antagonistic Tellarite envoy is found dead, suspicion logically falls on the Vulcan Ambassador Sarek (Mark Lenard), with whom the Tellarite had just had a shoving match. Complicating matters is Sarek's medical condition, akin to a human heart attack, which will kill him without a lifesaving operation-and the only available blood donor aboard the Enterprise is Sarek's estranged son, Spock. While Kirk ferrets out a conspiracy to derail the conference, Spock agrees to aid his father, but reneges when his captain is wounded and command of the Enterprise falls to him. Further refining the character of Spock, as did "Amok Time" before it, Fontana's script illustrates its author's affinity for the three lead characters and makes excellent use of the established dramatic tensions between Kirk, Spock, and McCoy to drive the action of the script.

"The Trouble With Tribbles"
Written by David Gerrold  
Aired: Dec. 29, 1967

Echoing the ecological disaster presaged by the introduction of rabbits to the predator-free Australian Outback, Gerrold's teleplay finds the Enterprise crew at the mercy of the adorably cuddly but rapidly breeding tribbles when eccentric trader Cyrano Jones (Stanley Adams) unleashes the pests on a space station. Exacerbating the scenario is a hostile crew of Klingons who demand shore leave on the station, which is harboring a vital grain supply. First-time scribe David Gerrold's dream came true when he found himself in a position to pitch a story to his favorite TV show. Chronicling the episode's origins and production in a book of the same name, the 23-year-old Gerrold extols the virtues of preparedness and persistence in young writers while reporting his experience. Easily one of the best-known stories to those with only a passing familiarity with the series, "The Trouble With Tribbles" illustrates the tonal range inherent in the series format, with moments of hilarious comedy punctuating the more serious espionage plot. The episode is so iconic that spin-off Deep Space Nine used the story as a starting point for a 30th anniversary tribute, with the space station's crew racing to stop the assassination of Captain Kirk during the events of this episode. Combining original series footage with newly shot scenes, "Trials and Tribble-ations" provides an engaging counterpoint to the action of Gerrold's original story.  David Gerrold has done many things since the penning of this first pro writing episode experience and is a giant in the genre of sci fi and fantasy.

Of course, limiting any list of "best" episodes for an entire series to merely seven precludes any number of gems. Whether it's the submarine-style warfare of "Balance of Terror," the sinister parallel universe of "Mirror, Mirror," or Psycho novelist Robert Bloch's stellar take on Victorian serial killers in "Wolf in the Fold,", the series boasted an embarrassment of creative riches. Star trek's legacy is even more evident in its non-stop syndication (now re-energized by newly restored episodes featuring CGI makeovers for the show's special effects), its vast propagation (one animated series, four live-action spin-offs, 10 movies, and countless media tie-ins of all description, not to mention merchandising...), and most of all its devoted following- one certain to swell when Lost creator J.J. Abrams' planned film hits movie screens.

All in all, we seem almost assured of never-ending "Star Trek" across the universe... and BEYOND - no doubt inspiring countless other science fiction/fantasy creations!

Live long and prosper, Star Trek; and continue to..."Boldly go where no man has gone before" with "Infinite Diversity In Infinite Combinations"... FOREVER!