Fantastic Thank you  Thats extremely helpful  That biography contains details of his early and late life that do not exist in the other sources Ive got his time in Paris pretty well fleshed out  Slonimskys reminiscences in Perfect Pitch are full of juicy details  Im still trying to understand all the Orthodox religious references in some of my other sources eg two resurrections  Im a little out to sea on some of that  Its hard to write about his tone method without doing forbidden original research because it seems no one has really studied it in depth  Sitsky maybe more than anyone else  I really want to look at one of the scores  Now if only I had a public domain illustration or two   Anyhow now I can cite that biography thanks to you  Im presuming that the World Encyclopedia in Russian is a reliable source  Everything sounds right and matches up with Grove and the others Ive got  Cheers