There is perhaps no question that more quickly exposes the ignorance of plebeians and academics alike than this one: What is art? Because, as is soon apparent, everyone has their own answer – which often isn’t an answer at all. Something beautiful. Something new and challenging. Something with an indistinct je nais se quoi. But when asked what is an artist, there is but one answer: a person that sells his art. Exit Through the Gift Shop exposes and dances within the gulf between these two questions, documenting first the openness of the definition of art, and then those who make millions from its vagueness. Because when anything can be art, anyone can be an artist.

The film opens with a shadowed figure whose face is blurred telling us that the documentary we are about to see is made by him, even though it features footage shot by someone else, someone who originally wanted to make the documentary but ended up being the star of it instead. It’s an appropriate introduction to the backwards, prankish world we are about to enter.

We meet Thierry, a transplanted Frenchman who makes a fortune selling vintage clothes in Los Angeles, and then spends the rest of his free time filming everything and everyone. After meeting up with a cousin who glues Space Invader graffiti to Paris landmarks, Thierry soon becomes immersed within the underground world of street artists, following graffitists at night, climbing rooftops, jumping fences, and outrunning security guards. No one really understands why Thierry is filming; Thierry doesn’t understand himself; so he simply starts telling people he’s making a documentary about street art. As a “documentarian,” Thierry meets all the elite figures in the street art movement: Space Invader, Shepard Fairey, and – the crème de la crème – Banksy.

Banksy is the great white whale of street artists. He is more reclusive, more artistic, and more high-profile than his peers, leaving his mark in scores of world capitals. He is more than a graffitist, more than an artist; Banksy is a professional prankster, and he allows Thierry the “documentarian” to videotape his exploits. He shows Thierry his boxes of counterfeit bills, a million pounds worth, that he must keep hidden to avoid ten years in prison. He lets Thierry film his team hijack a London telephone booth, and distort its features before replacing it on the streets. (This phone booth eventually sells at auction for hundreds of thousands of dollars.) One stunt features Banksy’s artistic protest to the treatment of prisoners at Guantanamo Bay: he inflates a doll dressed as a prisoner, and ties it to a ride within Disneyland.

But we’re not watching Thierry’s documentary. Exit Through the Gift Shop is a film Banksy, the original subject, has editing using Thierry’s footage. And the final result is not so much a film about street art as it is about the modern art scene – a critique whose primary target is Thierry, the original "documentarian." You see, Theirry – while taking a break from filming – decides to become an artist himself. And, within a surprisingly short period of time, rises to the forefront of the modern art scene. He does so – as it seems – without knowledge what he’s doing, and – as it seems – without creating any art. Or anything that should be properly called art. Thierry seems no more an artist than a documentarian, and for Banksy, Thierry is the epitome of the anti-artist: an artist who defines his ability not on his product, but on his ability to sell his product.

But there’s something more going on. There are … holes. Reactions to the film will not be divided between those who like it and those who do not (because everyone will like it), but between those who believe it and those who do not. Because, after the credits roll, the audience has enough reason to doubt whether what we’ve just seen is a documentary at all, to wonder if what we’ve just seen is a counterfeit reality crafted by Banksy, the prank of all pranks: the creation of a counterfeit artist.

It’s hard to accept the film as it is. How do we know if what we’ve just watched is reality? Or as false as the counterfeit bills that Banksy has shown us – bills intended as art, but real enough to pass for currency, and thus, dangerous? And then the kicker: knowing Banksy is a prankster, what if the film is indeed real, but he wants us to suspect otherwise? And this discrepancy is at the heart of the film: what is art? Can it be defined? Does its definition depend on the art, the artist, or the consumer? Is Banksy any more of an artist than Thierry simply becau se he has nobler intentions, or is art like beauty? That is, only in the eye of the beholder? And what happens when those eyes don't look closely? For Banksy, this seems to be the ultimate sin: not an artist selling counterfeit art, but a public so out of touch that it can't tell the difference.