He's portraying real-life comic book writer Harvey Pekar of Cleveland, whose mordantly funny rants and musings celebrate the everyday down and outers of this world, the nation's true nerds and the pristine drudgery of flunky jobs.

As Pekar, Giamatti performs a soliloquy worthy of Shakespeare. "Who am I?" he wonders. And as he's speaking, the cinematic world around him first slowly evolves into a drawing of a room as it would appear in a comic book frame, then, through a window, becomes a filmed snowy street scene where Giamatti visits briefly before stepping back into the on-screen comic book.

"American Splendor" is like that. For 101 minutes, it often folds itself, reshapes itself, becoming this just before altering itself into that. Not only does Giamatti appear as Pekar in this full-fledged biopic, but Pekar himself shows up in documentary segments. He's there in animated form, too, appearing in the many different ways many different artists, including Robert Crumb, have drawn him for his comic books.

With so much going on, you might think "American Splendor" wouldn't have a chance of making sense or connecting with audiences. You'd be wrong.

The movie works. Beautifully.

"American Splendor" is the indie movie of the year. Co-written and co-directed by Shari Springer Berman and Robert Pulcini, the low-low budget film (about $3 million) already has won the top prize for drama at the Sundance Film Festival and a special prize for originality at the Cannes Film Festival.

Shot at a breakneck pace in 24 days, the movie is thrillingly inventive, charming when it needs to be, prickly when it has to be and, like a potter's wheel, constantly in motion as it shapes celluloid into visual art. Blessed with inspired and convincing performances, "American Splendor" expertly explores the life of a creative mind, snuggling up to all the neuroses exhibited by Pekar and everyone he meets.

The film starts, naturally, in Pekar's stomping ground of blue-collar Cleveland, where his second marriage is in full downward spiral. We are treated to revealing encounters with Pekar's co-workers, some as strange as he is, at his day-job as a veterans hospital clerk. He meets Robert Crumb, the cult comic book artist responsible for "Fritz the Cat." Slowly, Pekar becomes inspired to create his own comic book series called "American Splendor," a collection of random observations that are as much about nothing as TV's "Seinfeld."

There's his fast marriage to his third wife, Joyce, his memorable appearances on NBC's "Late Night with David Letterman," and, ultimately, his successful battle with cancer, which he and Joyce transformed into another comic book called "Our Cancer Year."

The story is intermingled with conversations with the real-life Pekar. The Letterman clips are a balance of actual footage and restaged events (NBC prohibited the filmmakers from using Pekar's final visit to the show which devolved into a boisterous, confrontational rant).

Giamatti, who has spent years demonstrating talent as a supporting character ("Man on the Moon," "The Negotiator," "Saving Private Ryan"), is a revelation. His ability to capture the physical nuances of Pekar -- the simultaneous expressions of both gloom-and-doom and glee -- is amazing. His voice, his eye movements become avenues toward Pekar's essence.

Equally great is Hope Davis (the daughter in "About Schmidt" and Campbell Scott's spouse in "The Secret Lives of Dentists") as Pekar's wife, Joyce, who, despite her own obvious peculiarities, seems to be the most normal person in the story.

It's doubtful "American Splendor," being released slowly across the country in a small number of theaters, will become a mainstream sensation. It's too small a movie and an outright anomaly. It's not at all typical of a big-budget Hollywood biopic (it's the anti-"Gandhi").

Like the Brazilian gang-busters film "City of God" or the captivating documentary "Capturing the Friedmans," this is a movie where technique is tweaked to enhance the story and further the artform. Simply put, "American Splendor" is nothing short of splendid.