YOU HAVE TO understand that 1) Muhammad Ali is the public figure whom I most admire and 2) The Greatest was the only book I've read in my three years at Harvard that I wasn't able to put down.

I approached the book with some trepidation. Most autobiographies of athletes that I've read tend too often to be shallow, publicity-seeking, sensationalistic narratives, and I was fearful that Ali too would let me down. He didn't.

There were two early tipoffs that this wasn't going to be your run-of-the-mill sports hype. There are no pictures in the book ("What, no pictures?!" my roommate exclaimed as he leafed through the 413-page volume). And Ali begins the book by talking about his loss to Ken Norton, instead of starting out with a victory.

In ring parlance, there are no holds barred, no punches pulled. Ali is honest, not only about the personalities whom he encounters on his journey to become heavyweight champion of the world, but, more significantly, about himself as well.

The Greatest is certain to raise controversy because of the candid appraisals he makes of many people. For example, in talking about Wilt Chamberlain he says, "The most outstanding feature about Wilt was that he was the world's tallest Uncle Tom, which I believe forever made him unable to cope with Bill Russell on or off the basketball court." There are also some nice vignettes about people like Mayor Daley of Chicago and former Georgia governor Lester Maddox, and others of that ilk.

But The Greatest is at its best when Ali has others, and himself, analysing and talking about Ali. Ali is clearly very conscious of his media image, of a loud-mouth braggart, sadist (particularly after the Floyd Patterson bouts), and racist white hater. Ali wants to present himself in another light, to offer the public the "real" Ali. He tells us of his early sex life, and his flubbing of a chance with a hooker when he was 16 because he didn't know what to do. He dwells on his shyness with women (a shyness which one suspects still exists). There's a riotous conversation with Joe Frazier which Ali taped in Frazier's car prior to their first fight. And then there's the usual Ali irony and understatement. Of Rocky Marciano he says, "Rocky was quiet, peaceful, humble, not cocky or boastful. I can't stand heavyweights who talk too much."

But the humorous aspects of The Greatest are only momentary interludes, interspersed with what for the most part is a non-joking Ali who is talking straight from his heart. He tells us what it was like growing up in a poor black family living in the slums of a big city, barely able to feed himself. He talks a lot about his respect for and devotion to his parents and family. His reminiscences of his childhood days in Sunday School and roaming the streets are emotional and effective.

Ali talks affectionately not only about his own children, but also about the children of the men he defeated, and the anguish it brought him to see the pained expression on their faces at ringside as he was beating their fathers' faces in. "Children are a special love in the life of a heavyweight champion. They have a way of making him know what love is." Ali also allows his first wife to include her story as to why their marriage broke up. The Ali we get from her narrative is an often immature, single-minded, tyrannical husband.

The book also contains some tense, dramatic episodes, for instance, how Ali came to throw his gold medal into the Ohio River. He had been refused a hamburger in a whites only restaurant, shortly after his triumphant homecoming to Louisville, and then was attacked by a band of Naziinsignia-bearing motorcycle hoods who demanded that Ali give them the medal. Ali fought them off, but the whole experience finally sealed his disillusionment with white America.

THE primary reason that The Greatest comes off so well is the style with which Ali tells his story. From his Class Day speech last year and his news conference a few weeks ago, Harvard students are familiar with the boyish, disarming nature of Ali, the kind of innocence cum street smartness that allowed him to utter the simple yet profound statement that "I got no quarrel with them Viet Cong." Ali is able to put this style into his writing as well.

The Greatest is more than a sports book. Boxing fans will love it because it does say a lot about boxing and boxers, but it goes far beyond that. Ali's realist and he knows himself, and that sometime he will be finally defeated. Ali quotes Archie Moore (George Foreman's trainer) as saying, "Your time is coming. Your day will come."

But right now, Muhammad Ali is The Greatest. "The referee is raising my hand and the whole world is shouting 'Ali! Ali! Ali!'"