One of Hitchcock's favorite themes is the innocent man caught in a desperate situation, especially one is which he appears guilty of some crime. Sometimes the innocence or guilt is ambiguous; more often, it is clear to the viewer but unclear to the other characters in the film. Hitchcock's plots tend to revolve around characters' suspicions of each other and the efforts of the hero or heroine to discover who is truly guilty, and who is innocent. A sample of Hitchcock's films provides an opportunity to draw conclusions about his worldview regarding innocence.

In The Thirty-Nine Steps (1935), the innocence/guilt theme is clear: Robert Donat is an innocent man who must behave as though he were guilty in order to clear himself, and although by the end of the film he is indeed guilty of numerous crimes, it doesn't occur to the viewer to think of him as guilty because his crimes feel like crimes of necessity. Innocence versus guilt is more than a theme in Suspicion (1941); it is the question that makes the film interesting. The film plays a guessing game with the viewer: are the deaths of those around Johnny coincidence, (as Lina and therefore the viewer would like to believe), or is he a murderer (as it sometimes seems we must believe)? Young Charlie in Shadow of a Doubt (1943) is faced with much the same predicament as Lina when she begins to suspect that her beloved Uncle Charlie is the Merry Widow Murderer. This time the viewer is certain of Uncle Charlie's guilt before young Charlie is, giving Shadow of a Doubt an entirely different feeling. It is more psychological thriller than mystery.

Notorious (1946) is concerned with secret guilt. Alicia and Sebastian maintain an innocent façade even while they spy on and poison each other. This reverses the more typical Hitchcock scenario, in which the innocent behave as though they were guilty. Hitchcock returns to the innocent man idea in Strangers on a Train (1951), but with the twist that Guy is in the know, and carries the secret burden of psychological guilt inflicted by a death he has not-so-secretly wished for. Bruno's naiveté gives him an air of innocence despite his obvious guilt. Rear Window (1954) also gives us a protagonist in the know about a crime who suffers from a credibility problem. Is Jeffries a peeping Tom with an overactive imagination, or is Thorwald a murderer? Once again we see the innocent committing crimes as they try to reveal the truth, only this time they do it not to clear themselves, but to prove themselves. In Vertigo (1958), Hitchcock downplays Judy's involvement in Madeline's murder in order to preserve her appeal as the romantic lead; her principal crime seems to be deception, which the audience can more easily forgive her for. North by Northwest (1959), a study in genuine and apparent guilt, gives us the classic Hitchcock mistaken identity crisis. Vandamm has no problem convincing the authorities of his innocence, Eve's innocence or guilt is in constant question, and the only character who ever seems to be suspected of anything is the one the audience is sure is innocent—Thornhill. Psycho (1960), however, may be Hitchcock's most complex study of innocent and guilt because it forces the viewer to wrestle with the "guilty by reason of insanity" defense. Norman is physically guilty of murder, but is he morally responsible? Was the viewer paradoxically right when they believed his mother was the guilty party?

What is Hitchcock saying about guilt and innocence? He clearly believes in the possibility of innocence, even where guilt seems obvious. He is interested in telling stories that highlight how coincidence and circumstance can easily lead outsiders to the wrong conclusion, and imply that society is too quick to accept the simplest explanation, resisting more complex possibilities. In Hitchcock's world, deciding guilt and innocence is never simple, and justice's best hope seems to lie in the individual quest (often that of the accused) to find the guilty. Authorities are as likely to hinder the process as they are to help. Hitchcock believes in the ability of the individual to piece together the evidence and discover the truth, but implies that this detective work is best done by someone who is somehow involved, whether because they are themselves suspect, or involved with the guilty somehow (family member, lover, neighbor). Perhaps his point is that these are the only people who care deeply enough to unravel the truth. The frequent persecution of the innocent should not be interpreted as pessimism, however, for although in Hitchcock's world the innocent often struggle, in the end, guilt always comes to light and the innocent hero always gains something (often romantic love) from the experience. Guilt and innocence are often intricately bound up in questions of identity, as Hitchcock explores the slippery nature of both. Wary of seeing innocence or guilt in absolute terms, Hitchcock's films suggest that there are different kinds or degrees of both. Rather than viewing innocence or guilt in black and white terms, Hitchcock is more interested in exploring the spectrum of grays.