"When you're fat and ugly, you had better have a couple of high F's you can interpolate into your life." So says Maria Callas, the American-born Greek soprano who became the definitive diva of 20th-century opera, in Terrence McNally's celebrated 1995 play Master Class, now being given a strong production at the Paper Mill Playhouse, with a very fine Barbara Walsh in the leading role.

The two-act play, loosely based on a series of 12 master classes that Callas gave at the Juilliard School in 1971 that McNally observed, is essentially a one-woman monologue with short cameos from a trio of would-be opera singers, and incidental music by Bellini, Puccini, and Verdi that is performed by pianist [...]