THERE IS greatness in the extraordinary performances of Meryl Streep, Kevin Kline and Peter MacNicol, who endow the principal characters of "Sophie's Choice" with appealing, ultimately heartbreaking individuality and romantic glamor.

Beginning an exclusive first-run engagement today at the K-B Cinema, "Sophie's Choice" emerges as a remarkably accomplished and purified movie distillation of a dubious literary work. Dramatic improvements this compelling deserve to be cherished. Unless I miss my guess, this curiously exalted and powerful tearjerker is also destined to sweep the coming awards season off its feet.

Considering the source, William Styron's Pulitzer Prize-winning best-seller of 1979, I thought it a safe bet that "Sophie's Choice" would defy satisfying film adaptation. The director, Alan J. Pakula, seemed a capable and intelligent craftsman whose hit-and-miss track record ("The Sterile Cuckoo," "Klute," "Love and Pain and the Whole Damn Thing," "The Parallax View," "All the President's Men," "Starting Over," "Comes a Horseman," "Rollover") suggested a certain leaning toward death-wish subject matter. He was also making a belated debut as a screenwriter on this frightfully overwritten and underdramatized work of prestige fiction.

Pakula has responded to the challenge with an astute, gratifying feat of compression as a novice screenwriter, while ascending to a masterful level of control as a director. Beautifully orchestrating the contributions of a superlative crew and cast, Pakula enables the ill-fated summer idyll of the lovers Sophie and Nathan (Streep and Kline) and their devoted, uncomprehending young pal and chronicler-to-be Stingo (MacNicol) to unfold with unhurried deliberation and captivating tenderness. The sheer discretion of the presentation is so absorbing that you really begin to believe the usually botched illusion that you're sharing privileged moments -- of fleeting pleasure, growing companionship, shocking misunderstanding and then extended, melancholy confession -- with the characters and have an intimate stake in their lives.

In fact, the opening hour or so, dealing with Stingo's arrival at the boarding house across from Brooklyn's Prospect Park where he meets fellow tenants Sophie and Nathan, the introductory stages of their friendship and Sophie's account of how Nathan first endeared himself to her, evolves into one of the most savory stretches of exposition I've ever witnessed.

These three young actors are inventive and appealing and create such a lively, warm rapport that you really can't get enough of their presence and their skills. Because they make unusually effective claims on your feelings, it genuinely hurts when you're exposed to their sufferings and betrayals.

For example, Streep and Kline seem to me as sensational and stirring a pair of star-crossed movie lovers as Greta Garbo and John Gilbert (whom Kline strongly resembles) in their silent prime. They bring beauty and passion to the characters that could scarcely be anticipated from the book. Pakula's decision to use snatches of Styron's purplish prose as voice-over narration doesn't really work, but at one point, it reminds you of how decisively the material has been transformed by being enacted. When Stingo gushes about Nathan being "utterly, fatally glamorous" in the novel, you have to accept it as sheer assertion; in the movie, Kline is such a tangible dazzler that you never question his fascination for either Sophie or Stingo.

MacNicol, unimpressive as the juvenile hero of "Dragonslayer," makes something remarkably fresh and spontaneous out of a literary cliche' that almost always causes acute embarrassment when transposed to the screen -- the aspiring young novelist, destined to confront the tangled sweetness and bitterness of life. His Stingo is authenticated in ways Styron couldn't command -- the sound of his soft Tidewater accent, the authentic period look (he reminds you instantly of the young servicemen who fill the pages of Life magazine during the '40s).

Obviously, this method of authenticating character derives from the expressive resources at the command of actors, resources that can lead to immortality in a medium as sensitive to human appearance and nuance as the movies.

When the actors have also been encouraged to embody their roles as vividly as the company directed by Pakula, the odds of something special emerging from the creative process increase substantially. In this case, the increase is so abundant that it seems to lift the original material to a higher expressive power.

Pakula's exquisitely balanced restraint permits every nuance of performance to register with exceptional impact and resonance. The director's discretion also proves indispensable during the harrowing sequences that audiences are bound to dread in advance--Sophie's accounts of her imprisonment in Auschwitz that finally culminate in the devastating episode that explains the title. There's not a whisper of melodramatic excess or unearned emotional manipulation in Pakula's spare, laconic depiction of the death camps as both a nightmarish physical and psychological environment. In fact, he seems to authenticate the idea of the banality of evil by seeing Sophie's jailers and tormentors as undeniably human. No other fictional film has ever personalized the trauma and horror of this setting with the precision, dignity or impact Pakula demonstrates.

The movie press has been tempted to manufacture and promote a Meryl Streep bandwagon a bit before the subject herself fully justified the campaign. After Sophie, there's no point in holding out. This magnificent performance answers all lingering doubts about her ability to meet a major acting challenge. In fact, she's exploited the most daunting obstacle associated with the role--Sophie's Polish nationality, which initially inclined Pakula himself to believe that only a European actress could play it -- as the key technical instrument of her triumph. Streep plays scenes in German, Polish and a beautifully broken English, and the expressive effects she rings from that accented, halting English are phenomenal. I think it's impossible to reproduce the emotional flexibility and suggestiveness she achieves by revealing Sophie's terrible secrets in that fragile, haunted, searching-for-the-right-word speaking voice, but it does awesome things to you when her presence radiates from the screen.

Streep's performance involves feats of linguistic mimicry and modulation that are formidable. People are going to be marveling at and speculating about the vocal brilliance of her Sophie for generations to come. One despairs of suggesting a typical example without having her eccentric rhythms and wistful timbre to go with it, but she'll take a self-incriminating line and somehow break it in ways that churn you up: "I lied, because . . . you know why, I was afraid. I was afraid I'd . . . be left alone."

Pakula doesn't finesse every obstacle created by the source material. The continuity hits a couple of lulls before being revitalized by strong episodes, and I wish he'd invented a few more episodes, especially a clincher devoted to the final, fateful reunion of Sophie and Nathan. I'm not sure what could have been done to correct Styron's maddening failure to link Sophie's victimization with Nathan's self-destructiveness in a way that makes some dramatic sense.

Among the collaborative team one should certainly single out production designer George Jenkins, cinematographer Nestor Almendros and composer Marvin Hamlisch for exceptionally skillful and evocative support of the director's lucid, compassionate vision. Hamlisch's music is a model of unobtrusive underscoring and reinforcing of moods.

Two German actors who appear during the Auschwitz sequences -- Gunther Maria Halmer as the camp commandant Rudolf Hess and Karlheinz Hackl as the gratuitously malicious SS doctor who forces that awful choice on Sophie -- contribute superb performances in relatively brief roles. The level of acting sustained throughout the entire production takes your breath away.

Some movies are flexible and suggestible enough to stir you in many ways, but "Sophie's Choice" exemplifies what probably matters most to dramatic fiction on the screen -- it makes straight the way for a great company of actors to carry you to the heights of pathos.