The Path to the Nest of Spiders (1947)
by Italo Covino
Like many great novelists, Italo Covino had an ambivalent relationship with his first novel. The Path to the Nest of Spiders was derivative (of Ernest Hemingway's For Whom the Bell Tolls) and Calvino acknowledges as much in the Preface to the edition I read. In a sense, if you've read For Whom the Bell Tolls, you know what to expect in The Path to the Nest of Spiders, except it's set in Italy during World War II instead of Andalusian Spain during the Spanish Civil War.
Calvino's preface also situates The Path to the Nest of Spiders firmly in the "Italian Neorealist" genre. A canonical example of a film version of The Path to the Nest of Spiders is Salvatore Giuliano (1961) d. Francesco Rosi. That film was actually post World War II, about rebel-gangsters in Sicily in the 1950s. By comparison, The Path to the Nest of Spiders is strictly anti-Nazi/anti-Fascist World War II partisan stuff.
His description of neo-realism as being "in the air" after World War II ties in with interviews I've watched of contemporary artists like Roberto Rossellini. In the 40s and the 50s, even Fellini could be described as a neo-realist. See for example, I vitelloni (1953). That film is about as Italian neo-realist as you can get. Like Fellini, Calvino would go on to eclipse the neo-realist label, but would carry it's influence throughout his career.