Ranging from avant-garde theater to Wagner opera's, the several dozen sketches, paintings and ephemera in the small but worthwhile show chart the progressions of modern art and architecture across the stage. I was most interested in the pieces that depict strong, architectural set design, or as in a 1967 Lithuanian production of Porgy and Bess, woozy, forboding streetscapes rendered in a kind of pop art style.

The influence of masters from Kafka to Klimt to Corbu is apparent as you wander around the show, confirming that the early 20th century was a crucible of new artistic ideas that erupted across media, geography and time.

I also had another reason to pass the Morgan: to check out Renzo Piano's expansion and renovation of the courtyard linking JP Morgan's brownstone home to the McKim, Mead and White designed library. Though the library—done in the American Renaissance style—owes a clear debt to the ideas that came out of Italy some centuries beforehand, Piano's new building is as contemporary as it gets. A transparent glass box houses the lobby, gallery space, an education center and a cafe.

I found myself wandering the lobby, staring up at the soaring ceilings, wanting to ride again and again in the glass elevator and generally marvelling at a design that was by turns rapturously engaging and then seemed to disappear, bowing gracefully to the stately older buildings on both sides. So go for the Modern Stage and stay for the lobby. Oh, and the Morgan Library itself. That's not too shabby either, if you're into, you know, awe-inducing grandeur.