Who's Who in 'The X-Files' — From Mulder and Scully to the Lone Gunmen, a directory of characters from the sci-fi hit

The good news: The truth is out there. The bad news: It will probably stay there.

At least some of it, anyway. So far, in their ''mythology'' episodes — those conspiracy-packed shows that form the spine of the series — the producers have created a universe so paranoid and complex it would make Oliver Stone's head spin: alien corpses, mutant DNA, green toxic blood, devious vaccines, and, scariest of all, laser dentistry.

Just don't hold your breath for a tidy resolution. As creator Chris Carter says, ''I would like to think that because we can never truly know all the answers in life, that the show might follow that same route.''

But who knows? Like everything else associated with The X-Files, nothing is certain. ''I liken it to Lewis and Clark,'' he says. ''I know the direction I'm headed, but I don't know quite what I'll find on the way.''

Whatever he discovers — and whether you are an X-Files tyro or junkie — you'll need this very basic, twist-and-turn-filled map of the mythology to date.

SAMANTHA MULDER: If Mulder is this story's crusader, his sister Samantha is the holy grail. The G-man's unrelenting passion for The Truth and little green men stems from one incident: the abduction of his sibling, when he was 12 and she was 8, by aliens. (At least that's how the adult Fox remembered it during hypnotherapy.) Which brings us to ...

THE ALIENS: In Carter's universe, they come in all shapes and sizes: gender-bending sexaholics, light-warping predators, big-headed E.T. types, oily irradiating body-jumpers, and, soon, greasy parasitic worms. (Unless, of course, they aren't aliens at all — but let's not open that can of worms.)

The nature of their visits is unclear, but benefiting humanity probably isn't high on their list. And in that respect, extraterrestrials aren't all that different from X-Files humans. There are the occasional nice guys, but mostly the aliens are up to no good — as in the green-blooded shape-shifters, seemingly in cahoots with some very naughty men. Namely ...

THE SYNDICATE: This bunch of old white guys (The Syndicate's not big on affirmative action) apparently controls the world from their smoky, badly lit HQ on West 46th Street in New York City. The cast of characters includes a Marlon Brando wannabe known as the Fat Man and a dapper fellow called the Well-Manicured Man, who described his job thusly to Scully: ''We predict the future, and the best way to predict the future is to invent it.'' These men have links to the government — especially the CIA and the military — as well as a web of equally nefarious cohorts around the globe. They've been involved in all manner of malevolence since World War II, including Nazi-like testing on human subjects.

But their grandest passion is aliens, whom they have known about — or so they say — since a UFO crashed into the Pacific Ocean in 1953. The Syndicate appears to have joined forces with the shape-shifters (indeed, they employ one as a terminator, known simply as the Bounty Hunter) and has made contact with — or, at the very least, recovered DNA from — your garden-variety bug-eyed alien. Whether The Syndicate is controlling the aliens, or vice versa, remains to be seen. (And what is the Well-Manicured Man's interest in occasionally enlightening Mulder and Scully?) But the biggest mystery here is why these guys haven't all died from secondhand smoke.

THE PROJECT: It's nice to see us working hand in hand with our galactic neighbors. But this? The Syndicate and its alien collaborators have linked up on an enormous hush-hush scheme. The apparent goal: the creation of a super race — or, in one of many Holocaust references, a herrenvolk (master race). Like any big project, it's a step-by-step process.

Step 1: Set up a kick-ass filing system. Under the guise of providing smallpox vaccinations, inject everyone born since 1954 with a tiny DNA tag. After that, assign them an SEP (Smallpox Eradication Project) number and store the codes in the Social Security system.

Step 2: Research, research, research. Abduct thousands of human guinea pigs and perform various invasive experiments. (Just make sure they don't know if their captors are humans or aliens or both.) Also plant electronic doodads (seemingly made with alien technology) in their gums, nasal passages, and necks as either tracking devices or memory collectors.

Step 3: Human DNA, meet alien DNA. Using research perfected by evil scientists during World War II, fuse humans with extraterrestrials, possibly to create an uberarmy immune to biological warfare. Destroy all the evidence, dumping the little hybrid bodies (code name:''the merchandise'') into mass graves or buried boxcars.

Step 4: Make copies of your results. In other words, have fun with cloning.

The above information has come to us in maddening bits and pieces. In this season's opening episode, a rare benevolent alien, a clone named Jeremiah Smith, led Mulder to a bizarre Canadian compound filled with killer bees and rows and rows of unearthly shrubbery. Tending both were a community of mute, prepubescent clones, the girls dead ringers for an 8-year-old Samantha. ''Hegemony'' was how Smith explained the goings-on. ''A new origin of species.''

Actually, this wasn't the first Samantha clone to enter Mulder's life. In the second season, a woman who claimed to be his sister (all grown-up) implied that aliens have dwelt among us for years, colonizing the earth in an attempt to save our planet from ourselves; humans, as she put it, ''have failed in their stewardship of the planet.'' And by default these aliens will take over.

Sources deep inside The X-Files warn us to be skeptical of this simplistic if eco-friendly theory, which makes the aliens seem more PC than they proabably are. Whatever the aliens' intentions, they are yet to be disclosed. But one man who just might know is ...

CANCER MAN: This ''black-lunged son of a bitch,'' as Mulder once called him, has a résumé chockful of alleged evil deeds (everything from shooting JFK to rigging Buffalo Bills games and writing bad spy novels). Never without a smoking butt, he answers to The Syndicate, lurks about FBI HQ, and pokes around the Pentagon. But he has his own agenda as well — and part of it seems to involve keeping Mulder alive.

And this is perhaps the biggest X-Files conundrum: Why is a pesky, lowly FBI agent allowed to live despite having seen much of what The Syndicate is desperate to keep hidden? The answer appears to lie in Cancer Man, who, in devious ways, has prevented Mulder from perishing at the hands of all manner of creeps. Cancer Man thwarts our hero, taunts him, threatens him, but ultimately won't kill him. ''You risk turning one man's religion into a crusade,'' the raspy-voiced villain has said more than once.

And if you believe that, we've got a spaceship we'd like you to buy. Surely it couldn't be that simple. Besides, we've seen plenty of hints that where Mulder is concerned, things are very personal. Not only do we know that Cancer Man worked with Mulder's father (since the early '50s, at least), but last season's cliff-hanger threw a whole new wrench into the works: a possible close encounter of the romantic kind between Cancer Man and Mulder's mother (who, in perhaps the strangest twist of all, doesn't appear to have a first name). You can guess what kind of rumors circulated after that little revelation: Cancer Man is actually Mulder's father! We say: Way too obvious. In any event, there definitely was something fishy about ...

BILL MULDER: We know that he is mentioned in the government's MJ Files (top secret documents concerning extraterrestrial contact), that in addition to Cancer Man, he worked with the Well-Manicured Man, and that he was way into alien-human hybridization. (As a matter of fact, Cancer Man recently referred to it as ''Bill Mulder's project.'')

But unlike his cohorts, Bill apparently felt guilty about the twisted experiments and threatened to expose the whole thing. To shut him up, the powers that be had his daughter abducted. (In a Sophie's Choice homage, they let him pick between his two kids.) Mulder's mother understandably left him for that, and clearly knows more than she has revealed. (Keeping mum is probably a good idea: Mr. Mulder was murdered for attempting to spill the beans to his son.)

GOOD SAMARITANS: Fortunately, Mulder's crusade has its little helpers. Most notably, the agents' stern but admiring boss, Assistant Director Skinner, who has put his job and life on the line to protect Mulder and Scully — and he'll go even further in future episodes.

There's also the Lone Gunmen (Byers, Langly, Frohike), publishers of the underground Magic Bullet newsletter, who have occasionally provided guidance, although as with all obsessed conspiracy geeks, their allegations must be taken with a few shakers of salt. ''We like you because your theories are even crazier than ours,'' Frohike once told Mulder, a veritable messiah to fringe-dwelling truth seekers.

DEEP THROAT AND X: Less obviously in Mulder's corner were his former inside sources. The first came in the form of a graying, trench-coated man called Deep Throat (who is named not after the '70s porno flick, as has been reported, but the Watergate informant). Before his untimely death, this high-ranking official of something or other — knee-deep in alien cover-up with Cancer Man — regularly fed Mulder valuable tips, along with the occasional lie. ''There are some secrets that should remain secrets,'' he said once, after throwing Mulder off the track with a fake UFO photo. ''Truths that people are just not ready to know.''

After Deep Throat was deep-sixed by The Syndicate, presumably for alerting our heroes to Purity Control, Mulder found a replacement in X, a far pissier informant who worked for Cancer Man. Eventually, he too was slain by Syndicate henchmen, but not before he scrawled the name of a United Nations division (SRSG) in his own blood. There, Mulder has found Marita Covarrubias, who looks like she may be X's heir apparent.

Why Deep Throat and X were helping Mulder remains unclear. Was it out of guilt? Or, more interestingly, at the behest of Cancer Man? We may never know.

THE WILD CARD: Alex Krycek — former Cancer Man henchman (he killed Mulder's father), now a freelance ''player'' selling secrets to foreign governments — will (trust us) continue to be a thorn in the sides of The Syndicate and Mulder. Inhabited by aliens, beaten senseless, Krycek still manages to land on his feet. Just don't ask us about his arms.

THE GOVERNMENT: If you believe The X-Files, then Washington is a welter of conspiracies and secrets, a mass of covert black operation squads and ''groups within groups.'' And they're up to no good. In addition to the alien high jinks, Carter and Co. have accused the government of sleep-eradication experiments, mind control through subliminal television, and the spraying of psychosis-inducing toxins. Just a veritable smorgasbord of human rights abuses.

Of course, the nominal government — the one on C-SPAN — is probably merely a pawn, a servant to The Syndicate like all the rest of us shlubs. Although Mulder once had ''a friend on the Hill,'' his quest has taken him beyond what any politician knows. It's doubtful even the White House is aware of the real truth. As Cancer Man once noted, ''I work very hard to make sure no president even knows I exist.''

But at least Chris Carter knows. Or does he?