AN AMERICAN LIFE The Autobiography By Ronald Reagan Simon and Schuster. 748 pp. $24.95

DURING HIS quarter-century in public service Ronald Reagan was many things -- a charismatic hero to the right, a bogeyman to the left, a television performer of daunting skills, an architect of immense economic, political and social change -- but there was one distinction that eluded him. He was eloquent, passionate, amusing, infuriating, inspiring, trenchant, misguided, audacious, plucky; he was all of that and much more, but he was never, ever, dull.

Still, all things must come to all men, so now in the years of his retirement dullness has visited itself upon Ronald Wilson Reagan and caused him to commit An American Life. Billed on its dust-wrapper simply as "The Autobiography," it scarcely lives up to the name because it tells us nothing about the man who wrote it save that which we are able to extract by painful and time- consuming inference. Rather it is a state memoir, such as all presidents fortunate enough to survive to the end of their terms feel compelled to produce, and it is therefore a thoroughly soporific and mostly useless book.

All presidential memoirs, with the arguable exception of Harry Truman's, are cut from the same cloth. Every man who comes to the office yearns to place his imprint upon it, and every man who leaves the office is determined to dictate the precise shape of that imprint. Thus each of them turns pen to paper in the hope of swaying history's judgment, of presenting his own case in the best possible light. Thus too each of them writes a book that is unfailingly statesmanlike, polite, diplomatic -- and self-serving to the very core.

This is not a cardinal sin. Publishers who unaccountably sink millions in advance money into these memoirs may suffer when the day of reckoning arrives, but no one else is much put out by these exercises in presidential vanity; indeed we seem to shrug them off as among the less offensive perquisites of the office. No doubt this is in large measure because no one reads these memoirs -- with the obvious exception of Nixonologists digging into the innermost recesses of their subject's psyche -- but even more it is because they have almost no influence at all upon those for whom they are really written: the historians.

Certainly it is difficult to imagine that An American Life will be of any real use to those who, now and in the future, attempt to make sense of Ronald Reagan and the era to which his name has been given. Nothing of consequence here has failed to find a place in the public record, either that assembled by others or Reagan's own, as presented in his various political and autobiographical writings. The small-town childhood, the early career in radio, Hollywood and the Screen Actors Guild, General Electric and "Death Valley Days," California and the Kitchen Cabinet, the speech for Barry Goldwater, the race against Gerald Ford: it's still the same old story, as familiar by now as anything in 20th-century American mythology, and nothing in this memoir really alters our knowledge or understanding of it.

To be sure the reader with a taste for such exercises can practice divination through omission. Why, for example, are Reagan's eight-year marriage to Jane Wyman and their eventual divorce dismissed in a single paragraph containing precisely 48 carefully innocuous words? Why is the nomination of Robert Bork to the Supreme Court and the bitter fight that led to its rejection mentioned only once -- "I had to battle Congress" -- and then only as an unwelcome interruption in the larger business of negotiating with Gorbachev? Why do the various controversies of Edwin Meese's attorney-generalship go undiscussed here, save for a few passing acknowledgements of his inquiries, if that is the word for them, into the Iran-contra affair? Why is Caspar Weinberger's role in the defense buildup, and his willingness to play lightning rod for criticism of it, scarcely noticed?

Obviously all of these people and issues raise unpleasant memories, and, as all of us know, Ronald Reagan is something of a genius at pushing disagreeable matters into the background. So their passing presence in or utter absence from this chronicle really should come as no surprise, save to those readers who actually believed that Reagan would tell all about, say, the spat between his wife, Nancy, and his chief of staff, Donald Regan, or about the mischievous doings of Ollie North & Company. Like most former presidents basking in the well-heeled serenity of retirement, Reagan simply prefers to rise above it all when these irritating trivialities occur; and -- again, as all of us know -- being above it all is an art Reagan had elevated to high art long before his departure from the White House.

These matters safely behind him, Reagan can turn his attention to the true business of a presidential memoir, which is to cast himself in the role of peacemaker. That he does so should come as a complete surprise to virtually everyone who voted for or against him 10 years ago this week, but the presidency seems to have acquired an irresistible power to turn hawks into doves; even the man who enters office as the most ardent of saber-rattlers departs it at the helm of a plowshare, pleading with history to see his every action as one designed to make the lion lie down with the lamb.

So it is that Reagan writes, with a perfectly straight face: "The journey leading to arms reduction wasn't going to be short or easy. And I knew it had to begin with an increase of arms . . . If you were going to approach the Russians with a dove of peace in one hand, you had to have a sword in the other." We are to believe, this is to say, that what at the time gave every appearance of being a rather jingoistic stance toward the Soviet Union, not to mention an unprecedented peacetime bonanza for the defense industry, was in fact a subtle stratagem designed, as if by a mapmaker, to chart a path from Brezhnev to Gorbachev and thus from Afghanistan to Geneva.

To be sure that's how it worked out, but to claim as Reagan does that it was all planned this way is either disingenuous or self-deluding. That the American defense buildup helped force the Soviet Union into both perestroika and glasnost is indisputable, and for this we must be grateful even as we contemplate the legacy of its excesses of budgetary enthusiasm; but Reagan is asking us to accept ex post facto claims about his original motives and intentions that are unsupported by either the historical record or our individual and collective memories.

Still, that's what presidents do in their memoirs: make the best available case for themselves, even if this entails playing fast and loose with what might be called, at the risk of grandiosity, the truth. So too it is that in his discussion of the economic policies of his administration, Reagan writes: "In 1986, after almost two years of haggling with Congress, we got the tax reform bill we wanted." Never mind that Reagan was dragged kicking and screaming into tax reform (as opposed to tax cuts) or that the chief strategist of reform (his name goes unmentioned here) was Bill Bradley; it suits Reagan's convenience to represent himself not as the high priest of self-indulgence but as the architect of "reform." Somehow it seems doubtful that many historians will pay much attention.

Which raises the question: Is there in fact anything in these pages that will give them pause, that will make it easier for them to understand Ronald Reagan and his singularly complex, ambiguous legacy? Not really. Specialists in the intricacies of summitry may find some tidbits in his account of the various meetings with Gorbachev, but by and large these sections consist of interminable excerpts from public statements and correspondence -- putting on the record, as it were, what has been on it for some time. Similarly his account of the attempt upon his life, though brief, is arresting; but, again, it tells us nothing that we did not already know. INDEED, in these nearly 750 pages I could find only one tiny key to the mystery of Ronald Reagan. Early on he writes: "I was raised to believe that God has a plan for everyone and that seemingly random twists of fate are all a part of His plan. My mother . . . said all things were part of God's plan, even the most disheartening setbacks, and in the end, everything worked out for the best. If something went wrong, she said, you didn't let it get you down: You stepped away from it, stepped over it, and moved on."

Reagan has said this before, at various times and in various ways, but the frequency with which he refers in this book to "God's plan" leaves little doubt that this ebullient and energetic man, so praised by his supporters and feared by his opponents for an activism bordering on rashness, in actuality is a fatalist of the most passive sort, rolling with life's punches and rarely if ever questioning them. This explains a great deal, from his calm, composed response to his gunshot wounds to his easy indifference to the ethical laxity of so many of his closest loyalists to his ability to metamorphose from hawk to dove with scarcely a backward glance. To those of us constructed otherwise this may seem an unfathomable quirk of personality, but it is not perhaps an entirely undesirable quality to bring to so great a labor as the presidency.

It does on the other hand provide the temptations of complacency and evasion. If it's all God's plan, then none of it is your own fault. His protestations to the contrary notwithstanding, Reagan does not appear to be a genuinely religious man, but his reflexive, unquestioning assumption that everything is in the hands of a higher power who somehow is going to make it all turn out okay gives him a quick shortcut to self-delusion, such as that reducing federal income will actually increase it or that people who live in evil empires under godless communism belong to some subhuman species.

To give the man full credit, from time to time he is capable of stepping back from these illusions and re-examining them. "I'd always felt," he writes, "that from our deeds it must be clear to anyone that Americans were a moral people who starting at the birth of our nation had always used our power only as a force of good in the world," so he found it absolutely astonishing that Russians and others were "genuinely frightened of us." But his conversations with Gorbachev helped him understand this fear, and his trip to Moscow even persuaded him that Russians are people too; he never lost his quintessentially American faith in his country's moral rectitude, but he managed to learn enough about the other side to become more flexible than anyone could have predicted.

In the end, though, this sense of moral rectitude is likely to be what will most trouble the historians. Incapable of believing his country wrong, or himself wrong, Reagan encouraged his fellow citizens in that same belief. If he gave us a renewed self-respect, he led us beyond it into the conviction that there is a free lunch and we are entitled to it; the price we will end up paying for that little lesson in self-indulgence is only now beginning to become clear, as is the understanding that we will be paying it for generations, if not until kingdom come.