Mr. Beaty’s subject is Paul Robeson, the singer and actor who rose to the heights of his profession prior to and during World War II and then plummeted to the depths by his open admiration for equal treatment of people of color within the Soviet Union, an admiration that soured once Stalin came to power. Nevertheless, Mr. Robeson was called before the House UnAmerican Activities Committee, and like so many artists so called, he lost his prestige and his ability to work as an entertainer for years to come.