Why did Diane Hazzard give birth to six out-of-wedlock children when her brothers and her mother had died in their 30s of alcoholism? " The more I had, " she explains, " the more I thought I would be loved, to fill that empty space in my heart. But it always don’t turn out that way. "

Jennifer Dworkin’s remarkable, five-years-in-the-making documentary Love and Diane (opening this Friday at the Coolidge Corner) stands tall as a true-life multi-child Ma Joad tale. Diane, a stout, Bible-swearing matriarch, strives to keep her dumped-on, oft-defeated family together, assuring them that things will just get have to get better, in the face of gloomy poverty, unemployment without end, and an American system that seems out to crush them. The Hazzards, an African-American welfare family stuck in East New York, a slum section of Brooklyn, start off the film even more miserably than the Joad clan of Steinbeck’s The Grapes of Wrath. The Joads had roots, a home and land back in Oklahoma, but the Hazzards have been moving from one squalid rental unit to another for decades, through several have-not generations. Ma Joad is a devoted, charitable mother who’s worshipped by her flock. Diane Hazzard has the formidable task of earning the respect and affection of her psychologically bruised and deeply angry children. In earlier days, she was a desperate crack addict whose kids were all shipped off to Dickensian group homes while she got high. " Crack makes you heartless, cold, " she says.

Diane’s two sons are no mother-adoring Tom Joads but tragic, family-alienated lost causes. Charles, the oldest, is already dead when the movie begins, a teen suicide. Teenager Willie is a sulking phantom figure who walks through, then leaps out of, the documentary, choosing a precarious life on the streets over staying with his mom.

And yet . . . there’s also possibility. Three of Diane’s daughters seem to have made a shaky peace with their mom, taking her at her word when she says that she’s cured of her crack habit and that with Jesus’s help she has genuinely changed. She’s a caring mother now. And then there’s the baby Donyaeh, Diane’s cuddly, adorable grandchild, who’s born at the beginning of Love and Diane. In The Grapes of Wrath, Rosasharn’s infant arrives stillborn. In Love and Diane, Donyaeh is the great hope, and life seems to be looking up when hospital tests show him to be HIV-negative.

So what’s the rub? It’s Donyaeh’s mom, Love, the other half of the documentary’s title. This 19-year-old single parent, who is AIDS-positive and sometimes medically depressed, has never recovered her equilibrium, or her sense of self, after what she calls her " six years in hell " in a group home. She can’t forgive Diane for putting her there, and even now she accuses her mom of not caring. Love seethes with jealousy when grandma seems too attentive to baby Donyeah. She has what she calls " rage issues. "

Through most of Love and Diane’s tense, absorbing 155 minutes, Diane struggles to get Love to drop her animosity. " I cannot make up for the past, " she pleads. " You’ve got to stop blaming me for your life. " But for the most part Love is a stubborn victim, and her screwed-up existence is almost a self-fulfilling prophecy. After a hot-headed incident, Donyeah, whom she truly adores, is taken from her and placed in a foster home.

There’s so much drama, all of it real. Will Love get her child back? How will Donyeah’s devoted foster mother react to giving up the child she’s raising? Passed from hand to hand, will Donyeah remain happy as a toddler? Will Love and Diane reconcile? Another fascinating thread: can Diane find honorable employment and break the chain of welfare holding back the Hazzard clan? You have to see the movie if you want answers.

As for those in the audience who might denounce Love and Diane as politically incorrect, a documentary in which the white Dworkin stereotypes black people as being on the dole and residing in government-subsidized apartments, it’s worth noting that no one in the film mentions race. The Hazzards may be African-American, but they stand in for all Americans who are struggling for dignity below the poverty line, just as the white Joads do. And the dense, complex, humanist storytelling leaves stereotyping in the dust. The Hazzards live hard on screen, and those who see Love and Diane will be caring for them, rooting them on.

Gerald Peary can be reached at gpeary@world.std.com