I feel guilty about the fact that I have seen only two of Shaffer’s plays, Equus and Amadeus. Actually, they were movie versions of his plays, and I don’t even remember Equus all that well. But if there were an artist who could forgive the world for its indifference, it would be Shaffer, who in Amadeus’s Antonio Salieri created a character whose claim to greatness rests on his encounter with Mozart and the subsequent reckoning with his own insignificance. “I speak for all mediocrities in the world,” Salieri says in the movie, which Shaffer adapted from the stage. “I am their champion. I am their patron saint.” Shaffer’s insight was that the life of a true genius, while fascinating, does not have the pathos of one we can all recognize: a life that is mediocre, yes, but also ashamed of its imperfection and envious of the lucky few who appear to have been touched by God. (Shaffer underscored the contrast by turning Mozart into a guileless savant.) Salieri, himself a composer, is a study in despair: “Can you remember no melody of mine?” he angrily asks the priest who has come to receive his confession. Even one enduring melody is more than enough, and that Shaffer has.