http://www.forbes.com/technology/ebusiness.../ap2809210.html

For once, I agree with Cowing: Ligeti's music was an absolutely crucial part of "2001".

Bruce:

He was reportedly not pleased that his music was cut up for the film - a pity, really, for it gained him more listeners than ever he would have had otherwise!

The Alex North score, though well-meaning, just didn't cut the mustard.

Bob Shaw

I agree that the music is very nice, not only the well known "zarathustra theme", but also all other parts. Of course today it sounds a bit like "computer music" but this is not a problem. In some parts the music gives a very special ambient it would not have otherwise, like in the lunar flight scene.

In general the soundtrack is well done, especially to render the silence of space, when the heroe enters the airlock, of just after Hal refuses the entrance, there is a moment of silence with nothing moving. A thing few realisators would dare to do!