Three years and five pictures into his Hollywood career, Hitch had been having some trouble finding projects he was comfortable with. He had made a couple of adventure thrillers in the vein of his late 30s British films, but the old magic wasn't there. Finally, with Shadow of a Doubt he came upon a project that was right up his street. It represents a welcome return to the domestic murder dramas that had given him his earliest successes (The Lodger, Blackmail), with a storyline ideal for Hitchcock. It is the purest example of murder in a "normal" setting, bringing the audience uncomfortably close to the killer, helped along with plenty of the grisly gallows humour that the Master loved.
Hitch's British pictures had great charm and character, but they were often technically a little haphazard. By now though he knows exactly how to use the camera to manipulate the audience. He begins by carrying us into the story, sweeping in over the city through scenery both pretty and ugly, to home in on an average looking neighbourhood. From then on, every shot, move and edit is calculated to keep up the suspense and unfold the plot. Whereas those early films were swamped and sometimes spoiled by showy camera tricks, Hitch now uses those techniques sparingly, like playing a trump card. For example, he has Joseph Cotton look directly into the camera for a brief moment as he snatches the newspaper back from Theresa Wright. Another trick is to have the camera dolly back as a character advances, only at a faster speed than the actor is moving, which gives a very dizzying effect.
Special mention should also be made of Dimitri Tiomkin's score. Tiomkin was the best composer Hitch worked with before Bernard Hermann, and one of the few who really understood how a Hitchcock film needs to be scored. His sparse string arrangements really capture that sense of spiralling terror without overpowering the scene and turning it into melodrama. He interpolates Franz Lehar's Merry Widow waltz at just the right level, making it noticeable but never overstated throwing in just a bar or two at an opportune moment, sometimes disguising it in a minor key.
We also have a great cast lined up here. This is among Joseph Cotton's finest performances, which is unusual because Hitch was not a brilliant director of actors. I believe the reason is that, although his soft, honest features meant he usually played clean-cut good guys (as well as making him the perfect choice for the friendly uncle no-one would suspect), he was actually at his best when playing villains. That air of affected friendliness, which gives way to a deadpan monotone, is ironically far more convincing than when he attempted to play genuine niceness. Theresa Wright also does a brilliant job of handling her character's transition from childlike innocence to knowing cynicism. The icing on the cake is a couple of spot-on comic relief supporting parts from Henry Travers and Hume Cronyn.
It's quite appropriate that in his cameo for Shadow of a Doubt, Hitchcock is shown holding all the cards, because here he really did have all the elements working in his favour. It marks the beginning of his golden age and lays down the blueprint for such classics as Rear Window, Vertigo and Psycho. This is about as close to perfect as Hitchcock's pictures get.