"The X-Files" is an instrumental written and produced by American film and television composer Mark Snow.

On its parent album, The Truth and the Light: Music from the X-Files, the track is titled "Materia Primoris".

It is a remixed version of the original theme Snow composed for the science fiction television series The X-Files in 1993.

According to the "Behind the Truth" segment on the Season 1 DVD, Mark Snow created the echo effect on his famous X-Files theme song by accident.

At the same time Snow's original version was experiencing chart success, Italian producer DJ Dado covered the song.

The maxi-CD includes four remixes of Mark Snow's theme to the television series, The X-Files.