In the mid-20th century, American politicians saw subversion in popular music, from the anti-capitalist stanzas of Woody Guthrie’s “This Land Is Your Land,” to Malvina Reynolds’ anti-nuclear “What Have They Done to the Rain?” to Bob Dylan’s counterculture manifesto “Blowin’ in the Wind.” But in the Soviet Union, Joseph Stalin feared the power of classical music to undermine the party line, and his deputies carefully policed even the most illustrious Russian composers. Lapsing into atonality or dark, unresolved dissonance—the lingua franca of western avant-garde music of that era—could send a composer to the gulags of Siberia or an untimely demise.…