The music of Guendalina is attributed to “Piero Morgan”, an assumed name for the composer Piero Piccioni. Since it is well known as the pseudonym of the protagonist of the Montesi Case [a famous murder case of the time], it is also very likely that many people who see Lattuada’s film will pay more attention to the music track than they would ordinarily. Their opinion, we believe, would not be other than substantially positive. As ours has been, allowing due proportion between the aims of the film, the intentions of the director, what he has evidently asked from the composer, and the overall result of Guendalina. (…) With such a hot topical theme, the music could have been more corrosive, more bitterly penetrating, and in the critical sense indicative of a social connection common to our world. But then the cinematographic level would have to have been something else, not the discreetly polite approach of Lattuada.

On the level of Lattuada, then, “Morgan” has adopted a certain nonchalance, essentially limiting himself to photographing in backlight, or perhaps only with a certain perspective angling of lights and shades, consumer music of a certain style. The naïve snobbism (for example of speech) of the young girl is thus accompanied by a similar naïve musical style, where in substance the light music of the nightclubs and haunts of the Riviera, which marks the feeble and squalid amusements of the rich bourgeoisie beside the sea (and Guendalina belongs to a bourgeois family of this type), becomes the musical symbol of the protagonist, but in the sense of an unconscious and “pure” psychological and sentimental assimilation of the character into the background of a whole way of life.

Luigi Pestalozza, “Guendalina e Rififi,” Cinema Nuovo (no. 105, 15 April 1957)