Ethan Colburn’s review published on Letterboxd:
It's easy to see why this is Hitchcock's favorite.
Shadow of a Doubt builds its tension through its characters suspicions and not actions. Without Hitchcock's eye, this movie would be just fine, but he elevates it immensely. It is pure suspense, and I love the way you begin to doubt your own assumptions as the film goes on. There's something especially disturbing about evil coming from inside the house, as opposed to it being anonymous. Screenwriters tend to avoid giving two characters the same name but having the protagonist and antagonist both be named Charlie gives them a weird and disturbing connection that suggests she also has evil within her.
Joseph Cotten is great in this! He plays this part perfectly, acting creepy but it is also easy to see why the rest of the family wouldn't suspect anything suspicious. His acting is quite subtle, and I'm always happy to see him when he pops up in things.
I don't love Teresa Wright's performance. She was 25 at the time and acts like she's 9 occasionally, it doesn't make much sense to me. I think this movie would have been better with someone like Gene Tierney. I also felt her love story with the detective was unnecessary.
Hot tip: Peacock actually has a great library of old movies, including a lot of Hitchock classics.