Ernst Lubitsch was one of those movie artists able to match the frailties of human existence with a magisterial control that lets us revel in the streamlined fluency of the medium-call it movie. Hollywood had its share of such people, many of whom worked in sophisticated or screwball comedy-a genre in which appealing people make chumps of themselves. I'd like to propose this as the great genre of American moviemaking, and I offer Shop as something as “perfect” as the music boxes sold at Matuschek's (the Budapest store in Culver City), where the tunes played on the boxes are as bittersweet as Mozart. For this is a film about the difference between loving someone and being in love, a question that climaxes in one of the great shots in American film-the fragile face of Margaret Sullavan looking into an empty mailbox.