Im really really upset about this one.
His music along with that of Wendy Carlos, and the influence of Bob Moog literally changed my life. I designed and built my own synths in the 70s, and it was all down to those three.
If you've not heard of him, check out his Debussy transcriptions, including this, my all time favourite :
https://www.youtube.com/watch?v=lbdlhd1VR34
dh-4600synth-s by David W. Harris, on Flickr