While I do not claim to have known them, I did meet each of them briefly.
Merce Cunningham had provided a public question and answer session at Harvard around 1978. I always appreciated how he always used contemporary and experimental music for his dance works, and did not revert to pop or older music in his work as so many choreographers frequently do today. I recall one little detail about his comments that evening that have stuck in my mind all these years. He said that he is always very careful to organize works so that dances will not injure themselves by crashing into one another on the stage. He was willing to experiment with improvisatory structures, but not at the expense of personal safety.
Michael Steinberg was Director of Publications, editor, author, and annotator for the Boston Symphony Orchestra when I first came to Boston in the 70s.. I recall talking with him in the second floor cafe at Symphony Hall during the intermission. He had written program notes for the Berg Violin Concerto, and Steinberg and Gunther Schuller were looking at a photograph of the famous portrait of Alban Berg on display in the room (where Berg is looking out of a window above a painting of himself). Of all things, we spoke about the unusual circumstances surrounding Alban Berg's death.
George Russell was a fixture at the New England Conservatory. He was the quintessential jazz composer, and did not shy away from new techniques, electronic music, and avant garde methods of music making. He was a formative mentor to musician friends of mine (e.g. Marc Rossi), and I had met him around the time he won the MacArthur "genius award." His theoretical treatise "The Lydian Chromatic Concept of Tonal Organization" was developed in the 1950s, and had evolved into a significant jazz movement with a dedicated following of practitioners.
R.I.P.
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