The composers Richard Strauss and Dmitri Shostakovich had little in common musically, but each worked under one of the most brutal dictatorships of the mid 20th century. Many who regard Shostakovich as a tragic hero, for continuing to create his music while remaining in the Soviet Union, are far less generous to Strauss, who lived in Nazi Germany. When Hitler came to power, Strauss (1864–1949) was in his 70th year and universally regarded as a great composer. He outlived the Nazis by four years. Shostakovich (1906–75) was 11 years old at the time of the Russian Revolution, so he spent...