The soundtrack for the original version of No One Lives Forever (as well as the later Mac OS X port) was composed and produced by Guy Whitmore Guy Whitmore using DirectMusic technology. The game's score is an example of an adaptive score: the music changes smoothly during gameplay, depending on certain factors, such as whether the enemies are aware of the player's presence. Whitmore's task as composer was "to capture the flavor of the '50s/'60s spy genre, without infringing on any existing copyrights." In order to avoid any legal troubles over music from the James Bond franchise of films and games, Whitmore was initially asked to refrain from using brass instruments; a directive he compared to "being asked to produce a blues album without guitars". Influences for the score included German composer Peter Thomas, the soundtrack of the 1968 film Barbarella, and "and an array of Italian composers who did beautiful scores for low budget European erotic films."
Whitmore's score was not used for the PlayStation 2 version of the game. Instead, it featured original music by Rebecca Kneubuhl, and mixed by Gabriel Mann.
The No One Lives Forever theme song was created by Rich Ragsdale. Kneubuhl and Mann also provided vocals for the title theme.
"In the Lounge" 
The game was released with bonus 1960s-inspired music on the second CD. The songs available on this album, titled "In the Lounge", were not featured in the game, but were specifically written as extra material. The 9 songs were written by Rebecca Kneubuhl (who created the in-game score for the later PlayStation 2 port as well). The CD also features two songs by independent artists: "Void" by Red Delicious and "El Dorado" by Archie Thompson. These were selected for inclusion as part of a NOLF online "music search", organized by Fox Interactive and Indiespace.com.
A different version of "In the Lounge" was also created as an exclusive bonus for people who purchased the game from retail giant Best Buy  . This includes the same 9 original tracks, although in a slightly different order. It does not include the two pieces of independent music; however, it does feature Rich Ragsdale's NOLF title theme, as well as remixes of 6 of the original songs, by Gabriel Mann.