Reinaldo Arenas was a gifted Cuban novelist and poet whose life of poverty, hardship, revolution, censorship, imprisonment and exile never stemmed his formulation of passionate prose.

In "Before Night Falls," artist/filmmaker Julien Schnabel pays devotional homage to the writer with a soul-probing and beautifully cinematic adaptation of his memoirs, begun in a Cuban prison in 1973 and published posthumously after he succumbed to AIDS in New York in 1990.

The film, which tracks Arenas's entire life beginning with his childhood in a dirt-floored farmhouse, features dulcet, moving voice-overs from his poetry. It boasts powerful symbolism and political statements about freedom and persecution, not to mention cinematography that brings vividly to life the ironic contrast of Cuba's impoverished living conditions with its breathtaking beauty.

But what drives this engrossing biography is the potent but subtle, complex, intimate and magnetic portrayal of the author by Javier Bardem ("Boca a Boca"). With a natural, unaffected charisma and a generous smile full of both veritable joy and sonorous melancholy, Bardem is reminiscent of a Latin (and sober) Robert Downey, Jr. His brilliant performance gives such spirit and depth to Arenas's every nuance that it feels like he's sitting next to you in the theater, whispering his life story in your ear.

That story follows Arenas from his failing childhood farm to his idealistic teen years as a soldier in Castro's rebel army, then to the writing contest that led to a job at the national library where his creativity was nurtured by a mentor who lent him a comprehensive reading list including everything from the Bible to Melville to Kafka.

Schnabel -- whose only previous film was his controversial homage to fellow painter "Basquiat" -- treats Arenas's homosexuality quite matter-of-factly, although it is integral to many parts of the story. Sometimes this has the desired effect, making his sexual preference a non-issue from the audience's point of view. However, this biography is so thorough that at other times it feels incomplete because no mention is made of when he realized he was gay or of any internal struggles Arenas may have had with his sexuality, especially considering the culture in which he was raised.

The film is more focused on the political. As Castro cracks down on the intellectual community in the early 1970s, Arenas is forced to publish his work overseas after being censored at home. He watches a close friend confess falsely on television to crimes against the state, and before long he's a fugitive himself -- until his capture and imprisonment as a "rapist, murderer and CIA agent."

(One of the film's most wrenching episodes is when Arenas himself breaks under interrogation. Given the chance to go free, he betrays himself, writing "All the work I have done before now is garbage. I deny my homosexual condition. I am converted into a man by this revolution.")

Every moment up to this point is utterly absorbing, and the 133-minute film only begins to drag after Arenas's escape to the United States in the Mariel Harbor boatlift, during which Castro allowed undesirables (gays, ex-cons, the mentally ill) to leave Cuba en masse. Once he becomes stricken with AIDS, "Before Night Falls" takes 15 minutes too long to wind down and it becomes a get-on-with-it deathwatch.

But even with its shortcomings, this is one of the most passionately told screen biographies ever made.