The X-Files (TV Series 1993-2002) In one of the longest-running science fiction series in network TV history, FBI special agents investigate unexplained, mind-bending cases known as "X-Files." Though the government is convinced that the outlandish reports are false, conspiracy theorist Fox Mulder (David Duchovny) and realist Dana Scully (Gillian Anderson), for most of the series, stop at nothing to prove that "the truth is out there." Series creator Chris Carter also serves as executive producer of the thrilling pop-culture phenomenon.