(...) Already at the start, when he lies recumbent and listless in his seedy room, Uncle Charlie is a man visibly tired of life. Young Charlie also lies recumbent when we first see her, but she’s dissatisfied rather than listless, she wants something better from life, she’s reaching out for something wonderful that she thinks he represents. She’s animated by her dreams, while his seem spent. If the waltzing couples are an image the uncle and niece share in their minds, they share it from opposite perspectives: he has been through that dream of glamour and romance and come out the other end, having decided that, as he tells her after she finds out his secret,“ The world’s a hell.” Stories of the double often end in suicide. It’s fitting that the jaded uncle, despairing of life, would have his double, the spirited niece who bears his name, put an end to it all for him.
Gilberto Perez, Hitchcock's Family Romance: Allegory in Shadow of a Doubt.










