In Martin Ritt's film of Norma Rae (at the Hollywood), Sally Field gets so far into character you lose consciousness of her technique - there hasn't been a performance of this calibre by an American actress since Jane Fonda's in Klute. The screenwriters, Irving Ravetch and Harriet Frank Jr., have taken the real story of union organizer Crystal Lee and mixed it with incidents from the lives of several other militant Southern women.

For additional information on the film, check out these Web sites. They will open in a new browser window: • From Script to Screen: Norma Rae - Background on the film • Internet Movie Database: Norma Rae • Whysanity (movie monologue page): Ye Shall Inherit - A union organizer's speech to a meeting of Norma Rae's co-workers

The homogenization has resulted in a bona-fide folk heroine on par with Cicely Tyson in Sounder (also directed by Ritt) or The Autobiography of Miss Jane Pittman. It's a once-in-a-lifetime time role, and Miss Field squeezes it for every ounce of juice it harbors, without once appearing to apply pressure stronger than a lover's caress. Like Fred Astaire, she's in the business of making the impossible appear inevitable.

When Reuben (Ron Leibman, TV's Kaz), an advance man from the Textile Workers Union of America, arrives in Henleyville, Norma Rae's sour grapes are ripe for squeezing - she's broken up with a travelling salesman, the mill is making her mother deaf and living with her parents is driving her around a dead-end bend.

Just when you think this is going to be a predictable pairing of union man and maid, the movie throws a switch and Sonny (Beau Bridges), a crackling cracker, wins Norma Rae's heart - a good portion of which is located somewhere below her navel, as she lets Sonny know when he proposes. Kiss me, she orders, and if that's all right, everything else will be.

Ritt and his screenwriters carefully calibrate Norma Rae's odyssey to social consciousness. In a moving scene in a country-western hangout, Norma Rae talks about her past without a trace of self-pity. Sonny, sitting beside her, is asked by Reuben what he does when the fact that he's underpaid and overworked gets to him. I just wash down the beer, he replies defensively.

Norma Rae, never one to settle for what is offered or expected, eventually devotes her considerable energies to Reuben's cause - which she now understands as her own - and the film becomes a warm but realistic celebration of the working class's drive toward self-determination.

At a time when unions are unpopular, Ritt has taken a chance that viewers will respond to Norma Rae's plight. It was a chance that needed taking: there are unions and there are unions, and anyone who has spent time in the rural South will not quarrel with Ritt's even-handed contemporary depiction. (Two union bigwigs are image conscious; Reuben is irritatingly abrasive when dealing with management; Southern racism is shown as crossing class barriers.)

Their evident belief in this movie's message seems to have exerted a sobering effect on all the actors. Leibman does his finest, most understated work to date; Bridges holds his jejune charm in check, offering a dimensional performance that overcomes the significant obstacle of scanty screen time; and with practically no lines at all, Barbara Baxley captures the lights and shadows in Momma's life as vividly as in a Walker Evans photograph.

In the end, though, this is Sally Field's movie. Her performance - hyperbole completely aside - is peerless, one of the major achievements by an actress in the movies of any place and of any time.

Reuben tells Norma Rae that when he wants a smart, loud, profane, sloppy, hardworking woman he'll call on her. From now on, when directors want legerdemain that becomes art, they're going to call on Sally Field.