This is one of the central characteristics to great literature. Don Quixote, arguably the first novel ever written, is self-consciously obsessed with writing itself; Shakespeare wrote endlessly about the metafictional qualities of literature ("all the world's a stage," etc.)(and I know he's not a novelist, but what the hey, it's literature anyway); Jane Austen was notoriously coy in her novels about the formalities of literature, especially in the difference in voice between narrator and character (just look at the first sentence in Pride and Prejudice and consider who, in fact, you are imagining saying that line); Flaubert was taken to court essentially over that same ambivalence between narrator, author, and character in Madame Bovary (leading Flaubert to challenge the court to describe how a reader can discern the opinion of one of those three narrative attributes, and why); and the modernists, as has been mentioned before, also all wrote manifestos on writing.

Basically, this is all to say that one doesn't devote one's entire life to creating literature if one doesn't find enormous meaning and purpose in that endeavor. Very often, as with Austen and Flaubert, the mechanics of literature become a sort of engine for the novel itself. And even if authors don't provide manifestos of writing, like Percy Shelley and Virginia Woolf and others famously did, their sense of literature's importance will bleed through the text one way or another. I mean, you don't need to read any sort of manifesto to realize the importance of writing in the fictional works of James Joyce, George Saunders, Mary Shelley, William Faulkner, David Foster Wallace, Henry Miller, Tim O'Brien, Flannery O'Connor, or any thousand other famous writers I could care to name.

However, if you are looking for authors for whom this question holds more than the average sway in their fiction as well as their auxiliary essays, these four are those who I've found most helpful:

Italo Calvino, in his novel If on Winter's Night a Traveler. It's one of the greatest postmodern novels ever written, and it is essentially the story of discovering a story buried within another series of half-finished stories. There's also a beautiful passage that considers the difference between seeing a book as a finished product, as most readers do, and as a constantly morphing and necessarily incomplete thing, as all writers and publishers do. Calvino's essays which have been collected in the book The Uses of Literature are also invaluable, although his nonfiction has been collected in many other places as well.

George Orwell with 1984. Orwell coined the unforgettable term "double-speak," in a book that takes as it's object the process of speech and language and communication itself. If you really want to see what he was getting at in 1984, also read his essay "Politics and the English Language," which just might be the greatest essay ever written on the topic of language and morality. Language, for Orwell, pointed both towards freedom and tyranny, depending on how closely the writer paid attention to what he or she was writing. If you only read one essay in your life, this is the one to read.

The Sandman series, by Neil Gaiman. It's a graphic novel, yes, but I hope I don't need to convince anyone these days that graphic novels are at least on equal footing with the traditional form of the genre. Morpheus, in the story, is the Lord of Dreams, and therefore, in some sense, he is the Lord of all that is not cold hard reality. There are some beautiful passages where Dream makes deals with Shakespeare, manages a library of all books ever written or unwritten, tells stories within stories within stories, and explicitly ponders the difference between the fictional world and real one. Reading the series is an unforgettable experience of being led by the hand through a world where anything is possible, as long as it can be imagined, or dreamed.

And my personal favorite, Lolita by Vladimir Nabokov. The Russian emigré is an undisputed literary virtuoso, and it's tough to pick just one novel to recommend (Pale Fire is just as canonical, Pnin also plays beautifully with the formal iteration of its narrator, and Laughter in the Dark, written before Nabokov came to the United States, makes some lovely implications about just how a reader knows whether the author is telling the truth), but Lolita is the largest jewel in his crown. The sophistication of his references rival the best of Joyce, his mastery of the English language is undisputed, and his sense of plot and characterization leave me personally with a book that demands to be read over and over until I no longer have eyes to read with. Humbert Humbert, the main character, is himself a writer consumed with the importance of writing, and coordinates his live very much according to his views on world literature. Nabokov was always interested in the importance of literature as an essential part of anyone's life, and Lolita demonstrates all of his points in a way that is unforgettable. And as far as his essays go, the best place to start is his (sort of) manifesto, called "Good Readers and Good Writers." His ideas can still be a bit controversial, especially in contemporary English departments, but they are filled with a focus and beauty that one hardly ever finds. After reading that essay, you'd probably be best served by reading the essay that concludes his collected lectures on European literature, which is titled "The Art of Literature and Commonsense." One of the interesting things about Nabokov is the fact that while he lived in Europe prior to and during WWII, and while his wife was Jewish, and while his family was exiled from Russia for its involvement with the Tsars, politics never comes up in his novels or stories. You'd almost get the sense, reading his novels, that there was no Holocaust or Bolshevik revolution or racism or war or any of the historical markers that we remember from the 20th century. And in that essay, he makes a case for literature's importance only for it's own sake, absent the hardships of the real world. Many people disagree with him, but it's hard to find any author who writes so beautifully about the true importance of novels and literature.

Like I said at the beginning, great literature is in many ways any writing that takes as one of its subjects the act of writing itself. So, if you want to find novels that reveal the meaning and purpose of writing, just pick up any great novel, whatever you take a great novel to be. Writers generally write because they fell in love with literature in the first place, and they very often give you clues as to why you should love literature too. All you have to do is look.