[ROOSTER CROWING] LINDSAY ELLIS: Ever since the dawn of cinema, film has been this sort of little brother to the more heady, intellectual medium of novels.

And many film adaptations of literature leave viewers and critics saying, the book was better.

[MUSIC PLAYING] From "The Golden Compass" to "The Great Gatsby," from "The Hobbit" to "Harry Potter," and to "The Giver--" oh, "The Giver--" we find ourselves wondering why adaptations of beloved stories tend not to live up to the source material.

To quote literary and film theory professor Thomas Leitch, "The book will always be better than any adaptation because it is always better at being itself."

So what makes a good adaptation, especially of a great or popular book?

Can an adaptation ever really live up to the story you formed in your head?

Narrative adaptations, be they passed down through oral tradition or the written word, have a long and rich history that predates film.

Whether it's Goethe's "Faust" or Ovid's "The Metamorphosis," plays, ballets, and opera became the medium for popular stories to reach the pre-mass literacy masses.

However, film can accomplish what all of these other mediums can do while reaching an even wider audience.

It also frees visual adaptation from needing to stay on one relative plane, like a stage, for example.

But adaptation isn't just about changing the story.

It is translating the story to a totally different language, the language of film.

Film language includes cinematography, art directing, acting, editing, sound design, special effects, score, all of which work together to communicate ideas and emotions more quickly and viscerally than books can.

Film language can add to a story in ways that books can't.

"Fight Club" author, Chuck Palahniuk, saw the film adaptation as the best version of the story.

According to Palahniuk, "I was sort of embarrassed of the book because the movie had streamlined the plot and made it so much more effective and made connections that I had never thought to make."

But books as a medium have advantages, as well.

Books let us get inside characters heads.

Both "Fifty Shades of Grey" and "Ready Player One" have long, long passages where the protagonists muse to themselves about all sorts of things.

Ready Player One's" adaptation cuts most of Wade's internal monologue.

And "Fifty Shades of Grey's" cuts all of Anna's.

WOMAN: Ouch!

LINDSAY ELLIS: World building and scope is another thing that books can splurge on.

And only very recently have the budgets and technology of film and television even began to catch up with a novelist's imagination.

George RR Martin really went for it in his books, writing a complex story featuring dozens of characters, a few dragons, a zombie king, all waging war across multiple continents.

Until HBO came along and produced one of the most expensive TV shows ever made, Martin thought it was unadaptable.

And then there's Steven Spielberg, a master of adaptation who has no compunction about changing the source material.

"Jaws" transcended it's source material as pulpy, boilerplate thriller to become what many consider the beginning of the era of the blockbuster.

And in his adaptation of "Jurassic Park," Spielberg fleshes out the book's characters, changes some altogether, and adds straight-forward theming which wasn't really there in the book.

And then, of course, there's "Ready Player One," which, well, it's different from the book.

[VIDEO GAME BEEPING] But Spielberg's adaptations are generally well regarded.

Let's take a look at one that is remembered less kindly.

2005's "The Hitchhiker's Guide to the Galaxy" garnered pretty polar reactions upon its release.

Based on Douglas Adams' irreverent sci-fi comedy book series of the same name, itself an adaptation of a radio show-- PETER JONES: This is the story of The Hitchhiker's Guide to the Galaxy.

LINDSAY ELLIS: The initial response to this film was, well-- [SAD TONE] But what about this adaptation made it fail to capture the spirit of the book to so many people?

Creating an adaptation means incorporating the audience's paratext.

And paratext means everything that we, the audience, bring to the piece of media-- preconceptions, our worldview, our political views, what kind of day we had, whether or not we even read the source material.

All of these are forms of paratext.

A book published in 1952 will have to change to reflect the sensibilities of the audience in the 2000s, which is why the movie version of "The Lord of the Rings" is probably a lot more loud and bombastic than Tolkien envisioned.

"Heart of Darkness," which took place in colonial Africa, got a big upgrade to the Vietnam War in Francis Ford Coppola's "Apocalypse Now."

And with "War of the Worlds," Spielberg took a comment on British colonialism and recontextualized it for this post-9/11 moment in time.

Even genre is a form of paratext.

"Dr. Strangelove or How I Learned to Stop Worrying and Love the Bomb," which played the whole scenario as farcical, was based on a thriller called, "Red Alert," which plays the whole scenario as straight.

Paul Verhoeven took Robert Heinlein's "Starship Troopers," which as a book was pretty straight military science fiction, and pushes it so far, it is parodic.

"The Great Gatsby" is generally characterized as literary fiction, but its recent Baz Luhrmann's adaptation as a movie is more epic romance.

But while adaptations can run the gamut from great to not so great, it doesn't really answer why it feels like movies tend not to live up.

And a lot of that does have to do with medium.

Books are, by their very nature, more personal.

When you're reading a book, your brain is essentially acting as director, casting agent, cinematographer.

Is it any wonder that people get protective of the books that they love being turned into a major motion picture?

No, it's as if a middleman has stepped in between you and the literal movie of your dreams.

But that is not to say that either medium is superior.

Both mediums need to be appreciated on their own terms.

According to film critic Pauline Kael, "If some people would rather see the movie than read the book, this may be a fact of life that we must allow for.

But let's not pretend that people get the same things out of both or that nothing is lost."

[MUSIC PLAYING] "The Great American Read" is a new series on PBS about why we love to read, leading up to a nationwide vote on America's favorite novel.

Who decides America's favorite novel, you ask?

Well, that would be you, so head to PBS.org/greatamericanread to vote on your favorite book.

Check the link in the description for more details.