"It's as though Perry and I grew up in the same house, and then I went out the front door and he went out the back." Truman Capote (Philip Seymour Hoffman) is talking about the man he came to understand and write about in his 'non-fiction novel' "In Cold Blood" - Perry Smith, the soft-spoken, cold-blooded murderer, along with his partner Dick Hickock, of the four Clutter family members in rural Kansas in 1959. That line gives us a hint of what it was about Perry, Dick and the murders that so intrigued Capote; perhaps he saw a refraction of some part of himself when he read the newspaper story that November.

"Capote" is the film of the five years in Capote's life that began with his decision to write an article about the murders for The New Yorker. He goes to Kansas to visit the murder site and speak with the detective investigating the case, Alvin Dewey (Chris Cooper), hoping also to interview the murderers - one of whom, Perry, is actually being kept in a holding cell in the sheriff's apartment. With prescient intuition, Truman brings along his childhood friend Nelle Harper Lee (Catherine Keener), soon to publish her own blockbuster "To Kill A Mockingbird." Harper Lee runs interference for this quintessentially fey man, whose birdlike hands, quaint lisp and unshakable ego might well be startling to middle Americans. (He first shows up in a camel-hair duster that sweeps down to his ankles, but with only a look from Lee he soon exchanges it for a navy overcoat in the Kansas winter.)

Over the course of the years from then until the execution of the two men in 1964, the film lets us follow Truman as he finds a way to massage Perry - Hickock is hardly in the film from this point on - by coddling him, then abandoning him, then returning to him. Perry reveals more and more of himself, but will not talk about the murders. But without Perry's description of what happened at the Clutter house Truman has no ending for his story. It is a cat and mouse game, that Capote ultimately wins in one of the great, nailbiting scenes in recent years.

Every week, a critic sees actors in leading roles in all kinds of films; most performances are forgettable, some are worth a comment, a few stand out. Mr. Hoffman is beyond praise; he has left every bit of himself behind in order to become Capote, giving a performance so brave, so compelling that for the first time we can understand this strange, childlike man with the soft voice and doe eyes, fueled by alcohol and an endless supply of one-liners, and the steel will and self-discipline to put together a book that changed journalism forever. Hoffman's work here is a miracle.

And he is not alone; Keener as Harper Lee, knowing Truman too well to be awed by him, is quietly moving, witty, always aware. Chris Cooper is perfectly cast as the investigator, and the previously unknown Clifton Collins Jr. is believable as the sociopathic Perry. The film was directed by Bennett Miller, whose only previous work was a documentary about a New York tour-bus guide - a film that had been forgotten until a couple of years ago when it made the festival circuit. Miller shows an absolutely sure hand, letting scenes play to their proper length, choosing the perfect camera position, and trusting his actors to come through for him. They do, and they give us a brilliant work of film art.