The great pages in Terrence McNally’s Masterclass are those in which music takes stage. I know of no-one else who writes better about the act of music-making than Mr. McNally. Since the first student singer in the action sings very little, the words the playwright gives to Maria Callas as her teacher expand in our imagination into an imagined and sublime kind of singing, what we want it to be, what it ought to be. And most beautifully, he says that even the greenest student singer is connected to the long line of the piece, through herself, through her teacher, through the score, to the composer. The play is an in-house agon about being a singer. It is something the audience overhears.