For a broad view you might try "Music and Musical Life In Soviet Russia"
by Boris Schwarz. Get the updated 1983 edition. ISBN: 0-253-33956-1.
For a detailed understanding of his work in the Soviet environment you
might try "The New Shastakovich" by Ian MacDonald. ISBN: 1-55553-089-3.
These will be available in many public libraries or can be borrowed through
Inter-Library Loan services.
Cordially,
Harry Davis
Houston
(email: [log in to unmask])