One of the most controversial acts in the ever-controversial life of Dmitri Shostakovich was his tortured decision in 1960 to join the Communist Party. It is not mentioned in Testimony (1979) – the composer’s influential memoirs, collaboratively written with Solomon Volkov. But Volkov offered his own view, for the first time, in a Zoom chat the other day produced by PostClassical Ensemble. – Joseph Horowitz