In 1974 Stephen Sondheim and Burt Shevelove collaborated on a musical adaptation of [Aristophanes's] The Frogs…. In lyrics to a song entitled "The Sound of Poets" that might well express their writer's own artistic credo, the Chorus [in The Frogs] charges the poet to

                 Bring a sense of purpose,
                 Bring the taste of words,
                 Bring the sound of wit,
                 Bring the feel of passion,
                 Bring the glow of thought
                 To the darkening earth….

These are all things that Sondheim, the single most important force in the American musical theatre during the 1960s and 1970s, has achieved since that night twenty years ago when New York audiences first heard his lyrics in the revolutionary dance musical West Side Story. And if the myopic critics did not even mention his name the next morning in their notices, they have had numerous occasions since then to remedy their oversight in reviewing the...