One interesting aspect of these essays is the fact that they also examine the opposite quality that each of these essays implies, and Calvino praises both equally. One of my favorite lines from Lightness (which I include in English since I think more people will understand it): "Above all I hope to have shown that there is such a thing as a lightness of thoughtfulness, just as we all know that there is a lightness of frivolity. In fact, thoughtful lightness can make frivolity seem dull and heavy." I have returned to these essays many times over the years, and they highlight Calvino's awareness of his legacy as an author, a person in the publishing world, and a critic.
Calvino says, in Quickness, that the function of literature "is to communicate between things that are different simply because they are different, not blunting but even sharpening the differences between them, following the true bent of written language." Well said.