MEET TED and Joanna. Ted is your average on the rise Madison Avenue type, who catches cabs better than any human being in New York. Joanna is your average wife of your average on the rise Madison Avenue type. Ted and Joanna have a seven year-old child named Billy. Billy is very cute and precocious. They all live in a nice two-bedroom apartment on the Upper East Side.

Unfortunately for Ted, Joanna does not like being married to him any more. One night Joanna gives Ted her Bloomingdales charge card and Billy and goes off to California to find hereself. Mean-while, Ted learns to be daddy. Then Joanna comes back and tells Ted that she wants Billy back. A messy custody battle ensues.

Kramer vs. Kramer is one of those movies that does not come around often. A rare combination of deft acting and a believable story, it draws you in, holds your attention and forces you to become emotionally involved. It was not an easy movie to write or direct, but Robert Benton has succeeded in treading the fine line between washed-out soap opera and documentary. The result is a rare treat--a film that does not preach but makes its point, a film that makes you feel but does not jerk, a film that does not pretend to have all the answers.

If there is a single strength to Kramer, it is the acting. Dustin Hoffman (Ted) turns in one of the best performances of his career. Hoffman's strength lies in his research technique; when he agrees to a role, he studies the part, lives with people who resemble his character and compulsively perfects the nuances of the character. In Kramer, his strategy pays off. Hoffman's Ted Kramer is extraordinarily realistic, at once the ambitious young executive and the confused but loving father. His attention to detail and brilliant voice control--fast and agitated, quiet and pained--combine to add touches that few actors can.

Meryl Streep's Joanna is equally well-studied. Streep could have let herself fall into the role she played in Manhattan--the spiteful, surly bitch. But her Joanna is three-dimensional, the unquestioning young mother, the frustrated wife, the desperately independent career woman. She evokes sympathy where others would be satisfied with hatred. Justin Henry's Billy is not just another in the string of Tatum O'Neal-styled brats. The kid is no actor and the natural touches he adds--the smirk over a pint of chocolate chip ice cream, amusement at watching his father ruin the french toast--are indispensible to the realistic rapport built between father and son.

Benton's consistent direction and Nestor Almendros' crisp photography channel these superb performances into a cohesive film. Several of the best sequnces include Hoffman and downstairs neighbor Margaret (Jane Alexander). The interplay between the two (they were opposite each other in a short scene in All the President's Men) establishes a new type of man-woman-in-the-movies relationship; they are friends, very strong friends, but just that. Alexander's performance is crucial to the success of the film, as she moves with the audience's feelings, first sympathetic to Joanna's plight and gradually realizing that Ted's heart is in the right place.

ALL THIS IS not to argue, as many critics would have us believe, that Kramer is the film of the 1970s. Benton commits himself early on to the tightly-knit parallel construction and works well within this simple framework--the shopping scene and the breakfast scenes are terrific; but details go unexplored. Why doesn't Ted hire someone to take care of the kid? The bulk of the film develops the growing bond between Ted and Billy. All this time, Joanna presumably ests out in California making love to real estate developers and talking with $500-an-hour shrinks. She disappears from New York with $2000 and a leather purse...18 months later, she is back, a sportswear designer making $31,000 a year. We are as shocked as Hoffman when he hears the news in court--how did she get this job, why did she bother to come back--who is she anyway?

Benton plays disturbing games with time as well. Ted's boss sits him down for a little talk and we learn that Joanna has been gone for eight months. It seems more like three weeks. Forget that Ted could not possibly afford a snazzy, Upper East Side apartment on his $32,000 salary. And feel sorry for the guy whenever he ventures into a restaurant. Poor Ted just can't have a normal meal out. He sees Joanna for the first time in 18 months, gets fired, learns the court's verdict--all in chic, midtown restaurants. It's a wonder he keeps going out.

Kramer vs. Kramer is slick, almost contrived. The script manipulates at times. Every scene ends with a big laugh or a big cry. Benton edited the film perfectly and an hour and a half passes without notice. But his style is somehow out of synch with his subject. The rough edges that are an essential part of Ted and Joanna's break-up are masked inthe smooth flow.

Yet it all works--and works very well. When Billy falls from the jungle-jim, we feel Ted's pain and get tired as we run with him to the hospital. When Margaret takes the stand and pleads with Joanna to recognize Ted's love for Billy, we sympathize with all three of them. Kramer takes a tough and relevant subject and forces us to get involved. Go see this film--it's worth the emotional effort.