We don’t need a work of art to be perfect. As the literary critic Randall Jarrell, writing about Walt Whitman’s poem “Song of Myself,” said of one section: “There are faults in this passage, and they do not matter.” And yet, sometimes a production comes along that floats beatifically, in a place we call perfection. This jewel-like Barber of Seville, the work of the late director Ruth Berghaus and the designer Achim Freyer, circa 1968, is now 51 years old and still sparkles. Irreplaceable! —L.J.