Ahmad Saidullah in The Quarterly Conversation:
If the old-fashioned Anglo-American gumshoe mystery typifies the supremacy of reason and detection with an entrenched belief in the rationality of society, its laws, justice, and morals, the Italian noir novel is without any such optimism. It thwarts the deductions and logical propulsions that lead to neat endings. Italian noir exemplifies the Foucauldian instrumentality of reason in the “mansion of power,” to use Pier Paolo Pasolini’s phrase, with conspiracies, compromises, cover-ups, and unsolved crimes resulting.
Not surprisingly, noir’s popularity soared during the polarizing and corrupt rule of the Christian Democrats, led by Giulio Andreotti, when the mafia and over two hundred urban terrorist outfits confronted the violence of the state. Under Berlusconi, new themes have emerged. Open xenophobia, cultural racism, machismo, the derogation of labor and human rights, and the usurpation of press freedoms have divided Italy. This has given rise to intellectual and creative ferment, evident from the new wave of noir stories.
This engagement of writing with social realities is what separates Italian noir from, say, the mystery pieces that have emerged from peaceful, happy, uncorrupt, and relatively homicide-free Scandinavia.
More here.