This is a homage to books and the different types of fiction out there. The protagonist like in a Choose Your Own Adventure Book is You the reader (some of you might have to really imagine and think hard about it the further you go into the story however).
I have heard this book been refer to as ‘hypermetafiction’ and it definitely does make yourself aware as a reader along with the character of You in the story to feel like you have a part to play albeit being guided by Calvino throughout the story.
There are different styles of writing in this book which honours many different styles as well as translations. The book is structured so that one chapter follows the tale of You and the following chapter is based on a type of literature found in the story. A story within a story if you will.
I highly recommend this book and want you to read it so I won’t give too much away.