THEATER : Dust Bowl Diaries : Memoirs of people who came to California from the ravaged Midwest of the 1930s are woven into an emotional theater piece opening tonight.

One day in 1982, Peter Grego was lying on an air mattress in his friend’s back-yard swimming pool, and like any good Southern California sunbather, he was reading a script.

It wasn’t, though, a script in any traditional sense. It was the raw data of raw lives, individual memoirs of people who had left the ravaged Midwest Dust Bowl of the ‘30s for California. The recollections had been transcribed from tape recordings made by the California Odyssey Project, established to document and commemorate the epic of the Dust Bowl refugees.

These were the people whom novelist John Steinbeck met and transformed into figures of American tragedy in “The Grapes of Wrath.” Grego, lying there in the pool, was reading the memoirs as monologues that could be adapted to the stage. As a theater professor and director at Cal State Bakersfield, a campus situated in the heart of the land where the Dust Bowl people settled, he was in an ideal position to help create a play for the Odyssey Project.

But Grego knew this historical chapter only vaguely, and the theater world had basically ignored the story: It would be six years until playwright Frank Galati and Chicago’s Steppenwolf Theatre produced their Tony Award-winning version of “The Grapes of Wrath.” So the director didn’t know what to expect as he thumbed through the pages.

“I started crying right there,” says Grego. “I couldn’t believe that all 2,300 pages of transcribed material were as powerful as what I was reading. But I read on and realized they were.”

Grego turned the raw text into “From Dust Thou Art,” which he first staged in Bakersfield in 1983, then trimmed to its present form, which he is unveiling tonight at Cal State Northridge’s Little Theatre.

“Every time I’ve done this, it’s been a new kind of animal, with new challenges,” says Grego, who has been a CSUN professor since 1984.

“I took the whole summer of ’82 to go through the Odyssey Project’s volumes, picking out the strongest passages, piecing them together in a chronology that takes us from the devastated farmlands of Oklahoma and Texas to what looked to these people like the golden land of California. But it took working with the cast to put a shape to the sequences.”

Grego had never before adapted, let alone written, a play; his busy career as teacher and director hadn’t let him. Before he had any proper stage training, Grego took over a small Pennsylvania theater in 1968 (“My baptism of fire”). Grego went on to direct at his alma mater, Carnegie-Mellon University; at an English-language performance space in Berlin, and, in the last decade, at several Los Angeles-area theaters--from the Inner City Cultural Center to the International City Theatre, where he staged lauded productions of “Vanishing Points” and “A . . . My Name is Alice.” An encounter in 1985 with master Japanese theater artist Tadashi Suzuki took Grego to a hillside village in northern Japan. There, he trained in Suzuki’s performance method, which Grego sums up as “acting that begins at the soles of your feet, working from the outside in rather than the American style of going from the inside out.” Suzuki has asked Grego to return to Japan and become a full-fledged trainer, but Grego is delaying the move until he’s “mentally and physically ready.”

Those who have worked with Grego for years, such as lighting designer Paulie Jenkins, are struck by his ability to amass ideas and information: “He’s very visual--he studied art--so when I present him various design options, he knows what I’m talking about. Whenever I do a show with Peter, he sends me a five-pound mailing stuffed with his research. He’s the only director I’ve ever worked with who puts together such a vast supply of information. We may end up using a small portion of it, but for him, it’s all in the details.”

Of course, “From Dust Thou Art” was a child of research. But it has ended up being a work of emotional catharsis.

“In Bakersfield,” he recalls, “the text had this amazing resonance. There’s a passage in which a mother tells of how, out of despair, she nearly drowned herself and her children. Well, the same woman was in the audience with her children, and turned to them and said, ‘That was my story.’

“In one case, we pulled together the memories of a family who survived in a barn with a pig’s trough as a bed. The mother had nearly wiped out the memory, perhaps out of shame. Her daughter, who was a teen-ager during the Depression, held onto it as the worst time of her life. But her little brother, who was only 4, remembered it as the warmest time of his life, when he was most loved by his mother and sister.

“These aren’t just memories, but a multidimensional picture of a powerful historical and personal story. Like ‘Grapes of Wrath,’ it follows people from the Dust Bowl to California, and the new miseries they endured. But we had what Steinbeck didn’t have, which was their lives after the Depression. And since San Joaquin Valley people loathed Steinbeck’s book--they banned it in schools and libraries because they thought it depicted them as second-class citizens--we had to be careful not to create that impression.”

At CSUN, Grego is not only finishing a line of progress with the script but also encountering a new set of directorial difficulties. The play’s economized, intermissionless shape evolved after it was selected as winner of a 1991 national playwriting competition on “Themes of Rural America,” sponsored by the Missouri-based Lyceum Theatre.

“I was personally attracted to Peter’s play,” says Lyceum director Michael Bollinger, “because many of my relatives came out of the Depression. They had nothing, pulled up roots and made a better life for themselves. Beyond that, the play shows how widespread white on white discrimination was in those days.”

Once in Missouri, Grego found himself in the odd position of playwright, and disagreeing with director Bollinger’s intent to preserve the play’s original two-act structure.

“After several years away from it,” Grego says, “I had a chance to look at it with new eyes. The Missouri experience was wonderful, but it told me to make it shorter.” The new CSUN staging is letting him test what he thinks is a tauter, stronger version.

But while he had a professional cast in Missouri, Grego is taking his CSUN students into what is, for many of them, strange territory.

“I thought, for instance, that a scene that takes place in a Christian revivalist church would take care of itself,” he says. “But it wasn’t working in rehearsals and I found out why: Eleven of the cast are atheist and didn’t get the guilt and forgiveness business. Even a student who was Italian like me didn’t have my sort of Catholic upbringing. I took them to a local church, and now it’s sunk in. Last night’s rehearsal was right on the mark.” He stamps a finger on the desk for emphasis.

“The Dust Bowl saga is distant history for many students--for perhaps half the nation--and there have to be ways of bringing it back,” says Grego. “I took the cast up to Bakersfield, where we visited the Sunset Labor Camp,” a well-organized settlement popular with Dust Bowl refugees.

“It’s a setting in ‘Dust,’ and it’s the place where Steinbeck got the idea for ‘Grapes of Wrath.’ It’s powerful being in a place of living history, walking through it, sensing the sounds and smells--maybe even the ghosts of the place. I think it means much more to them now.”

Where and When What: “From Dust Thou Art.” Location: Cal State Northridge, Little Theatre, 18111 Nordhoff St., Northridge. Hours: Opens at 8 tonight and plays at 8 p.m. Thursdays through Saturdays, 5 p.m. Sundays and 7 p.m. Feb. 24, through March 7. Price: $4-$10. Call: (818) 885-3093.