I ran across a picture of Tanaquil Le Clercq on Instagram, and went down that rabbit hole and ran into a picture posted by Holly Brubach, in which she stated she was a friend of Tanny's and was starting to write her memoir. I found her homepage and saw this:
"I am currently working on a biography of Tanaquil Le Clercq, a ballerina for the New York City Ballet and George Balanchine’s last wife."
I am so looking forward to this!
More here: http://www.hollybrubach.com/news/