The X-Files is the cult science-fiction supernatural television series created by Chris Carter (Millennium) that starred David Duchovny and Gillian Anderson as Fox Mulder and Dana Scully - FBI agents who were placed in a special unofficial assignment known as the 'X-Files', in which they investigate cases that are associated with the paranormal. Mulder, as a true believer, had high interest in such cases, including, most notably, investigating (and proving) the existence of extraterrestrial life (as well as a far-reaching conspiracy denying knowledge thereof). This would become the background focus of the show. Outside of this story arc, the show concurrently dealt with additional cases involving other strange and unexplainable phenomenon, with Mulder purporting generally wild and unprovable theories as explanations. In both instances, Scully's primary role (as a rational and scientific type) was to analyze said findings (regarding them with scrutiny and skepticism) and find more logical conclusions. The series also stars Mitch Pileggi, Nicholas Lea and William B. Davis, with Robert Patrick and Annabeth Gish appearing in the main cast late in the show. The series aired for 9 seasons on the FOX network from 1993 to 2002 (making it, for a brief time, the longest-running North American science-fiction television series until beaten by Stargate SG-1), and would spawn two feature films: 1998's The X-Files: Fight the Future and 2008's The X-Files: I Want To Believe.
The following lists the television series seasons and films set in the universe of The X-Files: