AUGUSTO ROA BASTOS is himself a supreme find, maybe the most complex and brilliant, the densest-textured Latin American novelist of all. And I the Supreme, his lavish novel -- the first of his works to be translated into English -- makes me wonder, not just about the familiar and seemingly endless fecundity of Latin American imagination (which shows up in many more than a few fashionable novelists) but about the givens of Latin American life over the past two centuries. What a political demonology these novelists inherit, of ready-made, eccentric, monstrous tyrants such as they might invent only if they didn't otherwise exist. The price of admission to this Satan's gallery, however, has often enough been the right to reside in one's own country. For the past 40 years, for example, Augusto Roa Bastos has been exiled from his native Paraguay and living in France, teaching at the University of Toulouse until 1985.

What is it that makes Latin American tyrants, more than others, so usable -- for Latin Americans, of course, such as Alejo Carpentier (Reasons of State), Gabriel Garci'a Ma'rquez (The Autumn of the Patriarch), and Roa Bastos? To my knowledge there is only one good novel in English about even Hitler: Beryl Bainbridge's Young Adolf, and that is hardly epic in scope or proportions. We still await a commanding novel about Mussolini (though movie versions have been attempted, with disastrous results.) The Spanish novelist Juan Goytisolo has written about Spain rather than directly about Franco. And the tinpot tyrants of Central Europe go begging -- are they too dull to figure except as remote and inscrutable prefects?

Some streak of inventive madness seems missing in all but the Latin Americans, something that perhaps only tropical Catholicism can breed, something sadistically daffy that might fit well into Suetonius' Lives of the Caesars, something that appears a virtual monopoly of countries south of the border, where the mix of superstition and megalomania turns bloodily festive and charmingly ridiculous at the same time. I am thinking of tyrants whose mothers wish their sons had learned to read, tyrants who double as playboys in Paris, tyrants who "sell" part of the ocean, tyrants who, like the one Roa Bastos writes about, suspend all mail service with the outside world.

Perhaps the answer lies in something peculiar to Latin American imagination itself: unobligated to European and North American models, to logic, to what's verifiable, and perhaps the only continental imagination capable of inventing the weird things it finds on hand. Perhaps, in order to do such novels as I the Supreme, you have to be able to imagine what it would have been like to create that ostensibly "supreme" being yourself. Knowing that, you do a kind of reverse obeisance to the facts you then exploit, murmuring I could have invented you all, all the time. The confidence generated by that hypothetical triumph of literary creation carries over into the semi-documentary writing feat. Knowing you could have cooked up The Supreme, or Amin, you pillage his image with cogent vigor and so have energy to burn on minor matters, vesting them with unusual intensity.

As here. Put at its barest, I The Supreme imagines its way into the head and heart, the life and times, of Jose Gaspar Rodriguez de Francia (1766-1840), who in 1814 contrived to get himself declared Paraguay's "Supreme Dictator for Life." But that is like calling World War II an upset, an oak tree something invented to cast a shadow, a book a paper tile. Roa Bastos not only reconceives the life of tyrant Francia, but also makes him reconceive that reconception. At some point before beginning, Roa Bastos has all the "facts" in order; he knows what happened in history. Then he lets Francia, his own creation by now, play fast and loose with them, expressionistically, at the same time that he plays fast and loose with Francia himself. Indeed, Roa Bastos tampers not just twice but three times, handing over the facts to Policarpo Patin o, the tyrant's longtime secretary, who notes down (and alters) Francia's deathbed ponderings about his childhood in a Spanish monastery, his fellow tyrants in other countries, the egotistical sublimity that denied him family, friends, intimates, and the massive meteorite chained to his desk for having turned its tail on its place in the cosmos. (Is this the Paraguayan version of Garci'a Ma'rquez's jungle iceberg?)

Between them, Francis and Patin o turn the old romantic notion of the infinite I am into a literary carte blanche, aping Genesis (Let there be prose) and calling into question the beguiling array of smudges we like to call facts. If you read this book very slowly, you see things mutating in front of your eyes, not merely Rashomon-style with various conflicting accounts of the same event, but also in a timeless kaleidoscope whose import is: The world as perceived by humans is nothing but arbitrary images that correspond to nothing but themselves. We live amid a welter of glimpses we arrange and interpret in almost helpless subjectivity.

THE BOOK is littered with warnings: "I don't write history," Francia says, "I make it. I can remake it as I please, adjusting, stressing, enriching its meaning and truth . . . the order of the facts does not alter the product of the factors (my italics)." Roa Bastos writes with a cylindrical white-ivory pen containing a "memory lens" that turns everything into metaphor, which of course is what the five-page footnote describing the pen does to the pen itself. This footnote's author is someone called the Compiler, whose task is to join several modes of writing into a readable whole, from an outsized ledger called "the private notebook," some pages of which are burned, torn, illegible, crushed into a ball, worm-eaten, stuck together and petrified, or written in a hand other than Francia's, to a text that Patin o calls his "Perpetual Calendar," which at first sight seems more of an attempt at reliable, official narrative, but isn't. Rumination blurs both ledger and calendar just as incessant, engrossing footnotes blur them, not to mention ukases found nailed to the cathedral door, rough drafts of documents, excerpts from a logbook, bits scrawled at midnight or in "The Tutorial Voice," loose leaves, and a list of toys.

The effect of all such textual sea-changing, as you gradually get used to the Compiler's ways, is that of familiar-looking constellation rising and setting in the wrong order, at the wrong time. Pieced together from a thousand disparate pieces, this Supremiad samples all the ways there are of revealing someone through his miscellaneous writings. Indeed, the Compiler doesn't always identify his sources, so there you are, a willing accomplice among the motions of a mind learnedly overheard, and you are obliged, like all the king's horses and all the king's men, to put Humpty Dumpty Francia together again.

What a glory of echoing voices this Paraguayan portmanteau is, more Joycean than Corta'zar's Hopscotch, every bit as volcanic and visionary as Lezama Lima's Paradiso or Osman Lins' Avalovara. If the "Boom" of the Latin-American novel's world pre-eminence is over, then this novel begins the Boomerang, arriving 12 years after its publication in Spanish in Argentina, the second volume of Roa Bastos's trilogy.Demanding our time and indulgence, I The Supreme is a work of graceful, voluminous genius, an Everest of fiction, astoundingly predicated on a simple idea: Shall 19th-century Paraguay be itself or vanish into Argentina or Brazil?

The novel gives you both everything you think would come to mind apropos of that question as well as everything you think would not. Figure and ground merge together amid a blaze of puns, tirades, and dreams. "In Paraguay," we read, "time is so hard-pressed that it slows way down, mixing up the facts, shuffling things about, misplacing them . . . . You see that over there. No. It no longer exists. It has become an apparition." Strange to relate, this is very much the mood at the end of Samuel Beckett's Molloy ("Then I went back into the house and wrote, It is midnight. The rain is beating on the windows. It was not midnight. It was not raining.") When nothing is certain, everything matters, at least if you intend to write a novel; otherwise, nothing matters, and the novel vanishes into a cult of silence.

I the Supreme is vastly helped into our view by the superb translating of Helen Lane, who turns the impossible into child's play -- and that into a miraculous feat of lexical magnificence. It is beginning to look as if the novel, instead of coming back to North America and Europe after the Latin Amercian domination of the past 15 years or so, is to remain in those wizardly hands after all. Of magical realism we have perhaps only so far seen the tip. The iceberg refuses to melt or go away. Roa Bastos has trapped his meteor.