Half Nelson is that rarest of films, one that pulsates as if life is actually unfolding before our eyes. That's no small feat. Its characters feel real, vibrant, hopelessly complicated and, most impressive of all, unpredictable. It even takes a somewhat shopworn genre -- the crusading white teacher providing uplift to his disadvantaged minority students -- and promptly subverts audience expectations.

One of the best films of 2006, Half Nelson is also notable for a powerhouse performance by Ryan Gosling. Here he portrays Dan Dunne, a Brooklyn middle-school history teacher and girls' basketball coach of considerable smarts and charm. He is an unconventional educator, urging his students, most of whom are African-American and Latino, to view history as a never-ending push-and-pull of conflicting forces.

Dan's own conflicting forces take shape once his workday ends. Away from the classroom, he feeds a paralyzing addiction to crack cocaine. Dan's personal and professional worlds eventually collide one evening when he feeds his habit in a restroom stall at the school. There he is discovered by one of his female pupils, a 13-year-old latchkey kid named Drey (Shareeka Epps). Neither one knows how to handle the potentially explosive situation, but a tenuous friendship gradually develops between the pair.

It's an odd dynamic. The guarded and tight-lipped Drey is the stronger of the two. She is disappointed by her teacher's behavior, but not entirely surprised. Drey's brother is serving time in prison; while his offense is not made explicit, viewers presume it was drug-related since the brother's charismatic cohort, Frank (an excellent Anthony Mackie), peddles dope in the neighborhood. Dan tries to steer Drey away from Frank's overtures at friendship, but Dan, as Drey rightly observes, is a bit compromised when it comes to being a credible mentor.

Part of Half Nelson's brilliance is its continual thwarting of expectations. It would have been easy enough for director-writer Ryan Fleck and co-writer Anna Boden to stand and deliver yet another tale of a tough but openhearted teacher changing the lives of ghetto children. The filmmakers eschew such conventions, but neither do they settle for Dan finding salvation through the help of a wise-beyond-her-years girl.

Half Nelson (the title refers to a particularly discomfiting wrestling hold) resists pat situations. There is no heavy-handed explanation for Dan's addiction. Instead, the film lets its characters breathe, hearkening to the cinema verite of 1970s American cinema. The narrative ambles, elliptical in approach, forcing the audience to take an active role. Motivations are not easily discernible -- just as in real life. In the process, Half Nelson achieves a sublime poignancy that is, in a strange way, uplifting.

The acting is superb. Epps, who had no previous acting experience, proves to be an extraordinary find; she conveys much through her sharp, intelligent eyes. Mackie is similarly excellent as Frank, lending a memorable presence to what could have been a peripheral role. But this is easily Gosling's movie. He is mesmerizing and entirely deserving of his Oscar nomination.

As you would expect from a film released only a year ago, Half Nelson is a beautiful print. The picture, presented in anamorphic widescreen 1.78:1, boasts vivid colors and sharp detail. There is no discernible defect such as edge enhancement or aliasing.

In Dolby Digital 5.1, the sound is clear and crisp and, given its documentary-like style, offers surprisingly immersive audio. Moreover, it provides a clean showcase for the moody musical score by Broken Social Scene.

Subtitles are available in English and Spanish.

A commentary with Half Nelson director-writer Ryan Fleck and co-writer-producer-editor Anna Boden is relaxed and informative; the two have a wonderfully low-key rapport. They point out that many of the onscreen students in Dan's class were non-actors; Gosling had to work to grab their attention. Fleck and Boden also say Gosling is such a gifted actor that he can will himself to have a nosebleed. Take that, Brando.

Three deleted scenes combine for a three-minute, 29-second running time. One noteworthy scene left on the cutting-room floor shows Dan powerless to discipline Drey once she has discovered his secret.

Four extended scenes clock in for an aggregate length of three minutes and 23 seconds; they are of mild interest. The DVD includes almost seven minutes of outtakes and a Rhymefest music video for "Wanted."

With fully realized characters and the ability to surprise and challenge audience expectations, Half Nelson can be a devastating experience. Best of all is a captivating performance by Gosling, who finally gets to demonstrate his formidable acting chops. While the only DVD bonus of real merit is the Ryan Fleck-Anna Boden commentary, Half Nelson is still a worthy addition to the collection of any indie film buff.