In a way, it's looking backward that's the nub of the lawsuit. Artists routinely stand on the shoulders of their predecessors, channeling ideas through their personal lenses. Done creatively, it can provide whole new meanings to the original source. Francis Ford Coppola used Joseph Conrad's "Heart of Darkness" as the basis for "Apocalypse Now"; Conrad, in turn, relied on Dante's "Inferno."

Faulkner's books, too, are full of references to other works, particularly the King James Bible and Shakespeare's plays (which are both in the public domain).

"He even said, at moments when he was asked to give advice to young writers, that there's an element of artistic creation that is glorified stealing," says Watson. "In order to be bold and ambitious as an artist, you have to be willing to use whatever you find wherever you may find it."

Other artists have made frequent use of Faulkner. The Faulkner Institute at Southeast Missouri State University maintains a page of "Faulkner sightings."

Of course, when done less than creatively, it provides openings for the attorneys -- and in our remix-happy society, full of self-produced videos and sampled music, there's a fine line between creativity and copyright infringement (or, for that matter, outright piracy). YouTube alone is full of ripped-off video files and audio tracks, says Johnson.

"It's a morass out there of violations across the board," he says.

But it is sometimes hard to determine when the line is crossed. Artists and their estates have sued in the past when they believed their copyrights were being infringed upon. In 2001, Margaret Mitchell's estate sued author Alice Randall and publisher Houghton Mifflin over Randall's "The Wind Done Gone," a parody of "Gone With the Wind" told from the point of view of a slave. That case was eventually settled out of court, though an appeals court had upheld Randall's right to create the book.

Fair use is a "very gray area," says Julie Ahrens, who runs the Fair Use Project at Stanford University's Center for Internet and Society.

"There are lots of things that are not clear."

"I get things where people are like, 'Are you sure I can do this?' And the best I can say is, 'Yes, you should be able to,' " she says.

However, she doesn't see a problem with "Midnight in Paris" and "the past is not dead." Besides, the phrase has been used many times before -- in news headlines, TV shows and song lyrics. President Obama even used the line in perhaps the most famous speech of the 2008 campaign, known as "A More Perfect Union," which he delivered in response to the controversy involving his former pastor, the Rev. Jeremiah Wright. Obama's speech chronicled the challenges of race in America, and also misquoted Faulkner: "The past isn't dead and buried. In fact, it isn't even past," Obama said.

"The idea that one person can control the use of those particular words seems ridiculous to me," says Ahrens. "Any of kind of literary allusion is ordinarily celebrated. This seems to squarely fall in that tradition."

It seems like a lot of effort over a few words -- this case of the estate of a long-dead author going up against a multibillion-dollar Hollywood conglomerate. But the impact can be deep. Ahrens is worried about a chilling effect; Caplin is hoping that a brighter line can be introduced in the dim area of fair use.

It's nothing personal, he adds. He loved "Midnight in Paris." As executor, he's just looking out for the fiduciary responsibilities of the Faulkner estate, and he's willing to let a jury decide the merits of the copyright case.

"I'd love to have Woody Allen come down and have a free tour of (Faulkner's house) Rowan Oak," he says. "But if he wants to use any more of Mr. Faulkner, I would want him to give me a call and discuss a license fee."