When “The X-Files” debuted Sept. 10, 1993, it broke a lot of rules about television series. So at a press gathering, the creative group was asked what the show was aiming for. David Duchovny deadpanned, “Syndication.”

The series has surpassed even his expectations, running nine seasons (with an added two-season revival) and is still airing worldwide after 25 years.

On the day that the show debuted, Variety reviewer Tony Scott raved about the “ingenious script” by creator-exec producer Chris Carter. Scott continued, “The artful presentation gives TV sci-fi a boost … the series kicks off with drive and imagination.”

The show earned respectable ratings for Fox Broadcasting, in its first year of seven-nights-a-week programming. Soon there was a growing community of “X-Philes,” who used the new internet (aka “information superhighway”) to exchange ideas with other fans about the actions of FBI agents Mulder and Scully. The show quickly progressed from modest TV success to internet cult fave, then to global hit.

Fox Mulder (Duchovny) is a firm believer in the paranormal, while medical doctor Scully (Gillian Anderson) is always searching for rational answers. The male-female pairing was unusual, and Carter made sure they always respected each other as equals.

“I never want anything to be familiar on this show,” Carter told Brian Lowry for the 1995 book “The Truth Is Out There: The Official Guide to ‘The X-Files.’”

Carter did not want to give the audience easy answers. Every episode ended on a note of doubt as to whether the events had a supernatural or scientific explanation. The show was also innovative: The series was hard to define. Was it a crime show or sci-fi or horror — or what? The first few episodes featured UFOs, a Bigfoot-style killer, deadly organisms and a sinister computer. Conventional wisdom says that TV audiences want to know what to expect, but audiences liked the fact they were kept guessing about the direction in which each episode was headed.

The series’ slogan was “The truth is out there,” and there were frequent indications that the U.S. government was trying to conceal that truth, even from the two FBI investigators.

One-hour TV dramas often feature an ensemble of characters, because it offers greater flexibility for the writing staff, reduces pressure on the stars during production and, as a bonus, reduces their bargaining power for negotiations. But “X-Files” relied week after week on just Duchovny, Anderson and Mitch Pileggi, plus several recurring characters.

It made stars of them, and proved a great showcase for such writers as Vince Gilligan (who went on to “Breaking Bad” and “Better Call Saul”), Howard Gordon & Alex Gansa (“Homeland”), Frank Spotnitz (who holds the record for scripting 48 episodes) and actor-writer Darin Morgan, plus directors including Rob Bowman and Kim Manners.

In its original run, the show aired 202 episodes over nine seasons. A two-season revival began in 2016, with 16 more episodes, plus two big-screen editions over the years.

When the 1995 book came out from Lowry (a Variety alum who’s now CNN’s media critic), the series was only two years old. But Lowry wrote that Fox Broadcasting executives felt the series had “the potential for syndication for the next 30 years.” It still has five years to go, but it’s looking like a safe bet that it’s going to exceed that number.

The truth is still out there, and audiences are still eating it up.