Writing in the New Republic, Colin Dickey describes the influence of Thomas De Quincey’s 1823 essay “On the Knocking at the Gate in Macbeth” as it relates to the suspense genre:
There’s a moment in Alfred Hitchcock’s penultimate film, Frenzy, when the murderer Robert Rusk, a serial sexual predator, finds himself in a bit of a bind. Having just loaded the corpse of the hero’s girlfriend onto a truck carrying sacks of potatoes, Rusk realizes he’s left some incriminating evidence on the body. He climbs back up to retrieve it, but the truck begins moving, taking him further from London and into the country. As Rusk struggles to retrieve his tie-pin from his victim’s hand, he discovers rigor mortis has set in and he’s forced to break her fingers to get it free. It’s an elaborate, perversely comic scene in which a loathsome monster is strangely empathetic: Like any workaday slob, he’s made a small mistake in his job, and fixing it has turned into an increasingly complex comedy of errors. Who couldn’t sympathize with him? This is one of the great hallmarks of Hitchcockian suspense: The moment when, against all your instincts, you find yourself developing some measure of sympathy with the Devil.
More than a hundred years before Hitchcock began making films, Thomas De Quincey first pegged this affect in an 1823 essay, “On the Knocking at the Gate in Macbeth.” The essay turns on the moment when Macbeth is in the process murdering King Duncan. Macbeth is momentarily disturbed by MacDuff’s knocking at the gate, and he panics that his crime might be discovered. Why, when we know Macbeth’s crime to be immoral, do we switch allegiance, ever so momentarily, from the victims to the murderers?
De Quincey had no language available in the canon of Shakespearean criticism to describe how such a moment engendered “a peculiar awfulness and a depth of solemnity,” it fell to him to invent it. “Murder, in ordinary cases, where the sympathy is wholly directed to the case of the murdered person,” he reasons, “is an incident of coarse and vulgar horror; and for this reason that it flings the interest exclusively upon the natural but ignoble instinct by which we cleave to life.” This attitude to primal panic would never “suit the purposes of the poet.” What, then, must a poet do to elevate such a scene to high art? The only option: “He must throw the interest on the murderer.”
De Quincey and his subsequent essay “On Murder Considered as one of the Fine Arts” are treated at length in a chapter on the origins of the mystery genre in my new book Victoriana.