What is the main conflict in Master Class by Terrence McNally?

Although Master Class does delve into the triumphs and tragedies of Callas's life, its primary focus is the art of dramatic singing. As McNally's fictional version of Callas teaches her class, she explains to her students, two sopranos and a tenor, just what it takes to invest the music with real feeling, revealing as she does so how demanding the profession of opera singing is. She also reveals her own contradictory personality—proud and egotistical yet also vulnerable and self-pitying. In spite of all the flaws of its main character, however, Master Class, written by a man who has been a Callas fan since he was a teenager in high school, is a tribute to the dedication of a great singer and actress to her chosen art.