The book opens with a curious line: "You are about to begin reading Italo Calvino's new novel, If on a winter's night a traveler" (1.1). From the get-go, the book places you, the Reader, as its main character. Well then.
The story begins in a train station, where the narrator introduces himself as someone who is implicated in some sort of grand plot that he doesn't fully understand. Okay, Calvino, you've got our attention. Just when this story becomes interesting, though, it breaks off because of an error with the book's printing. Argh.
Frustrated, you (yes, you) return to the bookstore where you bought it and meet Ludmilla, an attractive young woman who's had the same problem. Now you not only want to read the book for its own sake, but to also have something to talk about with Ludmilla. In pursuit of Ludmilla, you agree to meet her at "the university," where you run into a nutty professor of dead languages named Uzzi-Tuzii. You also meet Lotaria, Ludmilla's academic sister, who reads novels only so she can project her political and overbearing theories onto them.
As the novel unfolds, you begin to read other books, only to have them break off the same way the first one did. Eventually, you go to the books' publisher and demand an explanation. A man named Mr. Cavedagna explains that a fraudulent translator named Ermes Marana has intentionally sent the entire publishing house (and possibly the publishing world) into chaos by swapping books' titles, contents, and authors until it seems almost impossible to set everything back in order. In the meantime, you continue to come across new novels that Marana has counterfeited only to find yourself completely engrossed. For one reason or another, though, you're never able to get past a first chapter.
Your search for an explanation sends you poring over Marana's letters, which eventually lead you to a reclusive old author of detective fiction named Silas Flannery. After confronting him, you learn that Marana might be in Ataguitania, and go there in search of—well, you're no longer entirely sure.
After landing in Ataguitania, you encounter a woman who goes by many different names, but who you're certain is Ludmilla's sister, Lotaria. When you arrive in the country, the police swipe the book you were trying to read (foiled again!) and you find yourself embroiled in some insane war between dictators and revolutionaries. Crestfallen after all your failed readings, you retreat to a library that seems to have copies of all the books you've begun to read.
While at the library, you encounter numerous readers, one of whom seems to point out a secret buried within all of the books you've been trying to read. (You'll have to finish the book to find out what.) After he explains to you that stories traditionally only have two endings, marriage and death, you decide that you want to marry Ludmilla.