When Ernst Krenek's opera Jonny spielt auf (Jonny plays on) opened in Leipzig in 1927, it became an instant and spectacular success. Performed in over a hundred cities and translated into a dozen languages, it became the most popular opera of this century. And Austrian-born Krenek, easily one of this century's most prolific major composers, became a wealthy man. Ten years later, however, he found himself a destitute refugee, fleeing to the United...