A scorned woman learns that crime diesn't pay. Bette Davis is great as the embittered sister who kills her recently widowed wealthy twin and assumes her identity. Consider this to be the continuation of Davis' 1940s film "A Stolen Life" where she also played two twins, one good and one bad.
Davis is convincing in helping us discern the differences between the two sisters who are totally dissimilar in temperament and style. Davis fans will be amused by the wealthy Maggie's declaration that she quit smoking years before while Edith puffs like a locomotive. It is Edith who gets the upper hand, taking over her sister's life and discovers that Maggie had a few horrifying secrets of her own that render her actually quite evil.
Karl Malden is excellent in his standard role as the police officer in love with the simple Edith; her down-to-earth protector. Peter Lawford doesn't appear until two-thirds into the movie as the sleazy gigolo lover of Maggie's who realizes what is going on uses it to blackmail Edith. He eventually gets his comeuppance in a great scene where he gets attacked by Edith's dogs. A good supporting cast, especially the religious in-law played by Estelle Winwood, a butler played by Cyril Delavanti and a gossipy socialite played by Jean Hagen.
What makes this film so compelling are the lengths that Bette has to go through to keep this charade going. From the handwriting, to recognizing friends and rooms in the mansion, Bette has a field day. The irony here is great when Bette realizes what a witch her sister was, but it's too late to do anything about it. Just seeing why Bette goes to the chair at the end is just unbelievable.
Bette Davis steals every scene she was in with her over-the-top kind of performing that she became known for. This is a campy delight; not only because it gives her the most clever lines, but is a reminder of how good an actress she was.