Music: 80 Years in Waltz Time

For most people, the mere mention of a Viennese operetta conjures up a waltz of post-Johann Strauss composers—Franz Lehar (The Merry Widow), Oskar Straus (The Chocolate Soldier), Emmerich Kalman (Countess Maritza). But beside their names belongs another: Robert Stolz. In his long career, Stolz has written almost as many operettas as the other three combined. Now 82. Stolz is the grand old man of operetta, the sole survivor of the golden age of popular Viennese music (1910-25). At Austria's open-air amphitheater on Lake Constance last week, Old Composer Stolz was still at work....