I SAW BILLY WILDER once. He and his wife were rushing out of a theatre into Shubert Alley in New York, while I stood in the shadows, waiting for a friend. Although I did not recognize him at first, he immediately attracted my attention. He was the fastest moving old man I had ever seen. He practically dragged his wife behind him as he zoomed towards 45th Street. His shoulders bobbed up and down: his cigarette slid from one corner of his month to the other: his eyes darted in every possible direction. A strange guy this Wilder. Who is he and what does he want from us? I wondered.

Wilder is by definition of course, the director of some of the most critically and financially successful movies to come out of Hollywood in the past twenty years. But what does he want from us? That's the tricky question, and one which must be asked, since Wilder's movies are not only among Hollywood's most successful but among its sickest as well.

The more of Wilder's stuff you see, the more you will be amazed by the man. He has done everything: trial drama ( Witness for the Prosecution ). Hollywood gothic ( Sunset Boulevard ). farce ( Some Like It Hot ), upper-crust romance ( Sabrina ). alcoholic melodrama ( The Lost Weekend ). He has done everything, and yet, he always wants the same thing from his audience-total distrust. Cynicism of the nastiest sort creeps into all of his work. While that doesn't exactly make his films pleasant, it certainly makes them unique in the history of American cinema.

Wilder just doesn't believe in anything or anybody. His movies are full of dishonest people, thieves and charlatans, cheats and frauds, phonies and liars of all types. In film after film, nobody ever actually is what he seems to be.

This is particularly evident in the weird love relationships in the films. Marilyn Monroe falls in love with Tony Curtis in Some Like It Hot -but this happens while Curtis is disguised as a woman. Ray Milland falls for Ginger Rogers in The Major and the Minor -only Miss Rogers happens to be disguised as a 12-year-old girl. William Holden feels love at first sight for Audrey Hepburn in Sabrina -but only because he thinks she's a cosmopolitan fashion plate rather than the chauffeur's daughter she really is.

Unlike the characters, the audience is let in on the mistaken identity aspects of the plot from the beginning-and that's the point. Wilder wants us to share with him his contemptuous laughter for all affairs human.

Yet, as nasty as Wilder is, he is also undeniably entertaining. I don't know quite how to explain that, except to say that he is intelligent enough to eschew a sledge hammer approach. In his best films-and his best films are gems-he keeps things moving so quickly and so lightly that you hardly have time to wince.

A number of his best pictures can be seen this week. (In fact, all of his best sixties work can be seen between tonight and Tuesday at the Welles.) Of those the one you cannot miss, whether you've already seen it or not, is Some Like It Hot. This comedy which revolves around two third-rate musicians who become members of an all-girl band to escape some murderous Chicago gangsters, is in every way Wilder's masterpiece. The nastiness is gentle but omnipresent: the evocation of the twenties' setting is beautifully detailed; the screenplay by Wilder and long-time collaborator I.A.L. Diamond is relentlessly hilarious. In addition, the amazing performances of Monroe and Curtis show Wilder's often underrated ability with actors.

Marilyn Monroe's performance in Some Like It Hot is particularly worth a revisit, for she is the ultimate Wilder victim. During the film she is constantly being manipulated and that upon. While her role takes on a special kind of poignance in the light of the disastrous end of her analogous personal life, the part is also important for showing Wilder's ultimate sympathy for the genuine and vulnerable individuals preyed scheming mass.

In three later pictures, The Apartment (1960), Irma La Douce (1963), and The Fortune Cookie (1966), Wilder again provides nice sympathetic victims (Jack Lemmon in the first two, Ron Rich in the latter). But, perhaps to counteract this, he makes the victimizers increasingly grotesque. Walter Matthau's conniving lawyer Whiplash Willie in the recent Fortune Cookie is Wilder's most terrifying caricature of humanity. Matthau, constantly shifting his eyes trying to locate the quickest buck, fails to say one generous thing during the entire picture. The cruelties of this character, as you might expect, contrast sharply with the mild evils of Wilder's first American feature, The Major and the Minor (1942), where the plot's major deception is Ginger Rogers' cheating of a railroad company out of $15. (In The Fortune Cookie Matthau tries to cheat an insurance company out of a million.)

Another marked result of the progression of Wilder's nastiness from Fortune is the clear phase-out of love and romance as important elements in the director's world view. In the latter, most recent picture, Wilder once and for all stops paying his rather vulgar homage to Ernst Lubitsch's lyricism and reduces love to a mere pawn in the chess game of human greed. Those who were fooled into thinking Wilder had some subconscious joie de vivre underneath his cynicism by his earlier pictures can't possibly believe that after The Fortune Cookie , where he shows us in no uncertain terms how much he despises us all. You don't exactly endear yourself to people if you do the kind of hatch work on the human race Billy Wilder does-and if I were him, I'd move quickly down dark alleys, too.