While Calvino is great, I wouldn't call someone who won a Nobel prize for literature underrated.

Calvino did not win the Nobel. The latest Italian to win it was Dario Fo.

Calvino is one of the most well know Italian writer abroad. Not underrated at all.

Incidentally translated into English by the same man that translated most of Umberto Eco's work, the late great William Weaver.

I remember that my teacher of Italian in high school asked us to read: "The Path to the Nest of Spiders".

That's Calvino's first novel, and it has a completely different style - and is much more boring as far as I remember- from everything he wrote afterwards. I think it was often chosen in Italian high schools for political reasons - it's a story about the Italian resistenza, the fight of partisans against fascists from which the modern Italian republic was born.

His subsequent novels and collections of short stories depart completely from that neo-realistic style. The way to describe them is possibly "a literary Bach" - his stories seem to develop fantastic themes in an endlessly imaginative way, exploring all the possibilities afforded by the theme, (loose) internal consistency and language. My favourites are "Cosmicomics" and "The invisible cities" .