Any books/literature on early 20th century Russian composers and music?

Posted this in r/classicalmusic, but wanted to try here as well.

I'm by no means an expert on classical music, but I do find that learning the history of composers and eras enhances my enjoyment of the music.

Lately, I've been listening to Rachmaninoff and Shostakovich and find their views, disagreements, and support with the Soviet government to be very interesting. Most of my knowledge comes from various articles and random online things, so I guess I am just wondering if there is a definitive (or generally recommended) book/author that I can read to learn a bit more about this era and region in terms of classical music?

Appreciate any suggestions!