Nearly 50 years after the Joad family made that memorable trek from dry and dusty Oklahoma to the fertile farmlands of California, "The Grapes of Wrath" has made a new journey from page to stage.

It's not the first theater adaptation of the Pulitzer Prize-winning novel by John Steinbeck, but the Steppenwolf Theater Company production at the Royal-George Theater, which closes Oct. 30, is certainly the most expensive. The $500,000 project also has the enthusiastic support of Elaine Steinbeck, the author's widow.The play stars two of the Steppenwolf troupe's biggest names, Gary Sinise and Terry Kinney, as well as guest artist Lois Smith as the indomitable Ma Joad.

AT&T picked up part of the tab for the three-hour production, which has a cast of 41, including four musicians who play an original score by Michael Smith. They perform on a spare, wooden-plank setting designed by Kevin Rigdon, who also did the costumes and lighting. The rough-hewn set covers the floor and back wall of the large stage.

But the man most responsible for the play, as well as its direction, is Frank Galati, a Chicago jack of all-theatrical trades who acts, writes, directs and teaches. The 44-year-old Galati first read "The Grapes of Wrath" in high school.

"It affected me in a number of ways that I've only begun to understand in the last couple of years," he said. "It turned me in the direction of literature, and my whole academic life as a student and as a teacher has been involved in the study of fiction."

Galati began adapting novels for the stage as a teacher at Northwestern University, where he directed a summer program that took students through the process.

One novel he wanted to adapt was "The Grapes of Wrath," but he couldn't get the rights. The idea lay dormant until Sinise, at the time Steppenwolf's artistic director, invited Galati to submit suggestions for possible productions.

"I thought `The Grapes of Wrath' would offer wonderful opportunities for an ensemble of exceptional actors," Galati said. Sinise, who had had some success with a production of Steinbeck's "Of Mice and Men" a few years earlier, agreed.

The Steinbeck estate, after extended negotiations, granted permission. By January of this year, Galati had done two drafts and began a third version after Randall Arney, Steppenwolf's artistic director and Stephen Eich, its managing director, decided to open the company's fall season with the work.

How does one boil down a sprawling novel of 30 chapters and nearly 600 pages? Galati started with a careful rereading.

"I needed to see the flow of the book," he said, "particularly, those incidents and episodes and characters that come to the surface as tent poles, a kind of spine on which the rest of the action hangs."

The novel, Galati says, is kind of an American ballad, and poses particular problems for a dramatist.

"On stage you're stuck with having to get a truck full of 13 people from Oklahoma to California by moving it a few feet," he said. "That compression, and telescoping and distortion of time and space is a very significant problem.

"The book has an A-B, A-B form of alternating chapters that go from the general to the specific. Steinbeck does a kind of landscape painting. Voice by voice, you get the sense of the great numbers of characters who are part of the epoch he was reflecting - the migrant workers, the land bosses, the contractors, the labor organizers, the businessmen. You also get a panorama of the Dust Bowl - Highway 66 from Oklahoma to California."

Galati needed to find a framework to dramatize the more general chapters. He found his answer in music.

"I contacted Smith, a wonderful Chicago composer and folk singer, and gave him sections of the novel that I had condensed into lyrics and asked him to set those lyrics to music," Galati says.

Have their efforts paid off?

The major Chicago reviews were divided about the show's merits. In the Chicago Sun-Times, Hedy Weiss called the production "breathtaking and emotionally wrenching . . . it would be an unpardonable sin if it did not receive an extended life, both in this country and abroad." Although the Chicago Tribune's Richard Christiansen described the play as "reverent" and "ambitious," he said "admiration for its effort must give way to disappointment in its results."

Galati feels "The Grapes of Wrath," both as a novel and a stage play, holds a particular relevance for people in 1988.

"There is this uncanny coincidence of the summer drought devastating American agriculture," he says. "And there's the theme of literally sacrificing the land, abusing and destroying the environment for the sake of capital gains. And we've still got migrant workers as the lowest rung of the social and economic ladder. Those themes remain as resonant today as they were in 1939."