You're browsing the GameFAQs Message Boards as a guest. Sign Up for free (or Log In if you already have an account) to be able to post messages, change how messages are displayed, and view media in posts.
I'm not the guy to ask about music, but since this board is pretty much a ghostown, I'll help you if I can. Wikipedia says: The soundtrack of Deus Ex, composed by Alexander Brandon, Dan Gardopée, Michiel van den Bos, and Reeves Gabrels, was praised by critics for complementing the gritty atmosphere predominant throughout the game with melodious and ambient music incorporated from a number of genres, including techno, jazz, and classical. The music sports a basic dynamic element, similar to the iMUSE system used in early 1990s LucasArts games; during play, the music will change to a different iteration of the currently playing song based on the player's actions, such as when the player starts a conversation, engages in combat, or transitions to the next level. A compact disc of the Deus Ex soundtrack was included in the Game of the Year edition and is not available for separate purchase. Notably, the soundtrack is not a direct audio rip from the game itself, however; it is a "remastering" of the soundtrack with added instruments and audio production. Originally only thirty tracks were included with the re-release, with tracks thirty-one through forty-one considered as extras. The PlayStation 2 port featured live, orchestral renditions of some tracks.
I couldn't make a lot of sense out of it, but basically it says that the music in the game is not only varied, but that it also changed when you did different actions. For stuff like it, I'd probably start with the composers and see if they have any more songs, then go from there.