(Welcome to Yesterday's Enterprises, a series where we explore every corner of the vast "Star Trek" universe. In this edition: a tribute to Dr. Phlox, one of the all-time-great "Trek" characters.)

For any neophytes that may be reading, the uniforms on "Star Trek" are colored to coordinate with their department. On the original series, those who are on the command track wear gold uniforms. Those in engineering or security wear red, and those involved with medicine or the sciences wear blue. For reasons that have never been adequately, canonically explained, gold and red switched functions at the start of "Star Trek: The Next Generation." The colored uniforms not only offer a very basic visual variety to the show — how dull if every single character wore the same clothes — but also lent a vital sense of structure to "Star Trek." A Federation starship was, audiences could immediately intuit, a massively complicated place that required multiple experts in various disciplines in order to function properly.

As such, each character would be infused with different concerns. A security officer would, for instance, be more concerned with keeping the ship safe than, say, a diplomatic command officer who would be more willing to take risks as a show of good faith. Multiple points of view, then, were baked into the very premise of the show, codifying Trek as its own kind of astral agora, a meeting place where various solutions to complex problems would be entertained.

Always existing somewhat apart from the other departments on "Star Trek" were the Starfleet medical officers. Each "Star Trek" series to date ("Star Trek: Prodigy" notwithstanding) has featured a clear-headed, professional CMO whose job it is to look after the physical well-being of the crew. They were often present on away missions — Dr. McCoy (DeForest Kelley) especially — but their concerns were often more immediate than the captain's mission. They only had to protect people from injury. The CMO's ethic was always more direct.

And that brings us to Dr. Phlox, one of the greatest "Star Trek" characters of all time.

Dr. Phlox

Of all the doctors on "Star Trek," Dr. Phlox (John Billingsley) from "Star Trek: Enterprise" was perhaps the best. A Denobulan — a species unseen until the premiere of "Enterprise" — Dr. Phlox was perhaps one of the happiest, most intelligent, most upbeat characters in all of "Star Trek" lore. Phlox served as the CMO aboard the original Enterprise, the very first long-range Starfleet vessel devoted to exploration and diplomacy. "Enterprise" took place about a century prior to the events of the original "Star Trek" and saw a starship crew operate in a world that had yet to invent common "Star Trek" technologies like shields, tractor beams, transporters (that were safe for living things) … and the Prime Directive. It was very much a frontiersmanship-forward show, and there was going to be no Federation safety net for the characters to fall back on.

The tone of "Enterprise" was very eager, but also nervous. Captain Archer (Scott Bakula), and the audience, could figure out "Star Trek" as it went along. Offering an emotional anchor to the proceedings was Dr. Phlox. He was on the ship as part of an inter-species exchange program, and he was eager and excited to serve. Phlox was no starry-eyed idealist, though — that was Dr. Bashir (Alexander Siddig) from "Star Trek: Deep Space Nine." Instead, Phlox was an experienced professional who had long ago come to the understanding that the straightest path to growth was through travel, exposure to other cultures, and learning to better himself. In brief, Phlox already represented Starfleet ideals before they were canonically codified. He was the gentle teacher, the doting professor, the patient parent, and the enthused tourist of "Enterprise."

But also something of a goofball.

Just Excited To Be Here

In the episode "A Night in Sickbay" (October 16, 2002), Captain Archer had to stay up through the wee hours concerned that his beloved Beagle Porthos was mysteriously sick. In his night sojourn, he spent a lot of time with Dr. Phlox and learned a lot about the way his CMO approached medicine. The captain found that Dr. Phlox had found curatives everywhere, including in the organs and excretions of the many exotic, alien animals he kept in sickbay. Also, thanks to his species' hibernation cycle — he sleeps for about a week at a time, then stays awake for months — Phlox was able to stay up with Archer, happy to psychoanalyze his fretting captain. Phlox possesses multiple degrees in medicine and psychiatry.

Even as he was performing surgery on a dog or asking about Archer's mother, Phlox radiated a strange, infectious jollity. Phlox perhaps reflected the excitement most Trekkies themselves would have, should they suddenly be transported into the imaginary world of "Star Trek."

Additionally, "Star Trek" doesn't necessarily have the best track record when it comes to progressive notions of sex and sexuality. Many early episodes of the 1966 series were staggeringly sexist, and Gene Roddenberry's notions of "free love for Gene" were too often part of the shows he created. In that tradition, "Enterprise" was typically a pretty lascivious show. It featured multiple scenes of crewmates having to strip to their underwear and slather each other with medicinal salve every time they returned from an away mission. The salve scenes were clearly part of a (pathetic) effort to boost ratings with oily skin.

Phlox's Sexuality

Phlox, standing counter to the show's own occasional bouts of adolescent lasciviousness, lived in a blissful polycule arrangement with multiple wives and husbands. When one of his wives visits the Enterprise, she flirts heavily with Trip Tucker (Connor Trinneer), the ship's engineer. At first, Tucker is taken aback, but is made uncomfortable when Dr. Phlox explains that his marriage is quite open. He has three wives and his wife has two additional husbands including him. Each one of her husbands also has three wives, and so on. When Tucker points out that it sounds complicated, Phlox smiles and says "Very." While the makers of "Enterprise" are nervously tittering about stripping the cast naked, Phlox is busy being happily polyamorous.

That's not to say that Phlox is not a character with complexity and principles. According to the way he practices medicine, the will of the patient takes precedence over his ability to heal. When asked to violate a patient's wishes, Phlox refuses. Captain Archer points out that he must first do no harm, to which the Denobulan comes back with "Hippocrates was a human." He aids people according to their wishes, and is concerned with the people in front of him. He is moral and insular and capable.

And, of course, all credit to Billinglsey for infusing Dr. Phlox with all of his most appealing qualities. Billingsley is an astonishingly good actor who played well with whoever he shared the screen with, immediately forming chemistry and a rapport. He gave the character his sense of awe, but also his maturity.

And what else does "Star Trek" pivot on than awe and maturity?

Read this next: Every Star Trek Show And Movie In Chronological Order

The post Why Enterprise's Dr. Phlox is the Greatest Star Trek Character appeared first on /Film.