Music of The X-Files franchise is composed and written by American Mark Snow; the franchise was created by Chris Carter. Snow has composed the music for all the franchise main releases (etc. television shows and films). Together with the show, the music was positively met by critics and viewers of the show alike. Snow has been nominated with over twenty awards and nominations for his music on the various franchise releases, but notably The X-Files. Among the most famous compositions of the franchise is the theme song for The X-Files. The theme reached #2 on the UK Singles Chart.
With The X-Files peaking in popularity in the mid-to-late 1990s, the music did too. When the show was hitting its peak in popularity, Carter created a spin off to the series, entitled Millennium which aired from 1996-1999. While never gaining as much attention as The X-Files, the show's theme song and soundtrack releases were well received by critics. The Lone Gunmen is the last television spin off of The X-Files which only aired for around two months. A soundtrack of the original music has been released in a set with music from Carter's other short lived Science Fiction series Harsh Realm. Snow returned to compose music for the franchise with the film, The X-Files: I Want to Believe.
Mark Snow got involved with The X-Files, since he was a good friend of executive producer R.W. Goodwin. When the production staff was talking about who was going to take the composing duties for the series, Chris Carter didn't know who to ask, in total about "10-15" people were looked at. But Goodwin pressed for Snow being the show's composer. Snow auditioned around three times, but didn't get any signs from the production staff if they wanted him. One day, Snow's agent called talking about the pilot episode, and hinted that he had got the part. At first Snow wasn't sure if he wanted to work on The X-Files, giving the reason that he felt they were "weird". So Snow eventually started to compose his music in Los Angeles, California, in which he would continue until the show's end.