In his conversations with Truffaut, Hitchcock confirmed that Dial M for Murder was a film he was compelled to make to honor the terms of a contract and which he considered a lesser work, one which he was not all that ambitious about. Nevertheless it is one of the most important and splendid films made by the master of suspense. Nine tenths of the film takes place in one interior set, like its predecessor Rope and the film that followed, Rear Window. This constraint provided Hitchcock with a vehicle for creating unity and impeccable logic, not to mention a stimulus for his virtuosity. Dial M for Murder was shot in 3-D; the use of three dimensionality is however nothing more here than an enormous and joyous redundancy, as even in the 2-D version, Hitchcock staged the action and shooting in the limited and confined space of the single interior with extraordinary depth. Hitchcock was not interested in using the new tool at its most shocking, and most of the time preferred just to put his camera in little niches at ground level. More than any of his other films, Dial M for Murder poses the question regarding Hitchcock’s virtuosity: was it used to express the theme of the film or to hide it? In some ways, one could say it did both…
Hitchcock’s genius – and his own public image – aimed at wrapping a dark reality within some perfect act of deception that seemed to him evidence, which he would then do everything to repel, that for some individuals the crowning achievement of their lives would be the crime they would commit. A secret disciple of De Quincey and his On Murder Considered as One of the Fine Arts, Hitchcock concocted, beside a handful of unsteady and neurotic criminals, many more who were perfectly comfortable and secure, satanic creatures whose crimes gave them their main reason to exist. Among them, the character played by Ray Milland is one of the most disturbing. He doesn’t quite pull off the perfect crime, but from a psychological point of view he is practically the perfect criminal: inventive, audacious, suave and supremely unflappable.
Hitchcock covered himself in a number of ways against what seemed to him to be an obvious fact (that some individuals are career criminals). He convinced himself and wanted to convince others that his films were meant solely to entertain, not meant to be taken seriously. He made sure that all of his films ended up with the moral “right” prevailing, even after that went out of style. Nevertheless in creating his characters he could not help but underline the intellectual superiority, charm, foppishness, seduction and tragic glow emanating from certain criminals compared to the guiltless and the representatives of the law, portrayed mainly as dull and largely insignificant, even when quite talented at what they did. Hitchcock then armed himself with a sense of humor (transmitted in this instance through the character of Inspector Hubbard played by John Williams). Like many Hollywood filmmakers, but in his case more for personal reasons more than any thoughts of morality, Hitchcock often buried the hidden meaning of his work within his seemingly more superficial films. As a result the more minor a film of his might seem to be, the more likely it is to be significant.

Jacques Lourcelles, Dictionnaire du cinéma. Les films, Robert Laffont, Paris 1992