What Latin Americans call El Boom -- the explosion of literary energy that has shaken the whole continent for nearly 20 years -- is beginning to reverberate at last in the United States.

One by one, the novels and short stories of Gabriel Garcia Marquez are coming out in paperback, and many of us have at least read his radiant "One Hundred Years of Solitude," with that electrifying first sentence, quite possibly the most seductive opening of any novel anytime:

"Many years later, as he faced the firing squad, Colonel Aureliano Buendia was to remember that distant afternoon when his father took him to discover ice."

There are others, of course, from Jorge Luis Borges to Julio Cortazar, who wrote the story that the film "Blowup" was based on. And many more quietly wait for us to find them.

As much as anyone, Demetrio Aguilera-Malta, Ecuador's foremost writer, was the man who set off this explosion. His 21 major novels, most of them untranslated, are virtually unknown in this country, though the University of Texas has just published an English version of "Seven Moons and Seven Serpents."

Firmly in the Latin tradition of activist writers, Aguilera-Malta covered the Republican in the Spanish Civil War, wrote for newspaper in Mexico, and now is the Ecuadorian ambassador to Mexico. He also paints. He is 70.

Aguilera-Malta was in town this week, appearing in a symposium at the Library of Congress and causing much excitement in the Latin American community here.

His translator was Gregory Rabassa, who teaches literature at Queens College. Rabassa is best known for his translations of Garcia Marquez, who held up the English publication of "One Hundred Years" for nearly two years because he would have no other translator than Rabassa.

Rabassa has translated many of the new Latin writers and won a National Book Award for his English version of Cortazar's "Rayuela."

Through Rabassa, Aguilera-Malta told how he and a few friends from the same town, the "Guayaquil group," started using the novel as a weapon for social justice and political comment.They covered the whole spectrum from "pure politicians to the politically pure," as he put it. He himself had always been more interested in ethics than in politics, and one of his themes was human freedom for the coastal peasants, the cholos.

While the writers range from the conservative Borges to the Marxist Garcia Marquez, covering a multitude of subjects, there do seem to be some common themes. Marquez's "The Autumn of the Patriarch," for instance, describes a wildly overripe and rotten military regime and its tyranny over the peasants, as well as their influence over dictator. "Seven Moons" imagines the return of Jesus to a corrupt society.

One way or another, through irony, fantas or parable, establishment complacence is exposed, consciousness is raised.

In her new book on Aguilera-Malta, Clementine Christos Rabassa, the translator's wife, speaks of the author's "portrayal of the new hero, who symbolizes Milton's heroic ideal of patience and martyrdom and is a collective image of Latin America's indigent and indigenous masses struggling for survival and social justice."

Another feature of the Guayaquil group was its new style, the so-called "magic realism," a direct expression of its demand for new ways of seeing, new ways of thinking. It is this technique, which runs together event and dream in the same vividly concrete terms, that Garcia Marquez picked up from the older writers.

"It's not limited to any one writer," said Aguilera-Malta, "not even to Latin-American writers. Look at Faulkner."

With its casual inclusion of fantasy in its everyday narrative, magic realism makes a natural vehicle for everything from invective to humor. No wonder it's called a revolutionary style.

As for the Boom, Aguilera-Malta was not entirely happy with it.

"More than anything else, it's a business," he said. "There are more publishers, more authors, more agents than ever before, taking advantage of circumstances: the fact that international fiction isn't very good right now, the novelty of their themes and techniques."

In a work, he said, a few good writers are pulling along the others as a locomotive pulls a train. He dislikes the publicity machine, the mutual admiration societies.

Though the modern Latin American novelist is by no means aloof from films -- both Aguilera-Malta and his wife have done film scripts -- there appears to be little danger that the richly imaginative, evocative magic realism will disintegrate into writing-for-the-movies.

Actor Anthony Quinn once offered Garcia Marquez $1 million for rights to "One Hundred Years." He was stiffly informed that the price was $5 million: in other words, forget it . . .

Observed Aquilera-Malta:

"There are stomach writers (only in it for the money) and there are writer writers. And there are two kinds of best-seller, the best-seller in space -- seen everywhere -- and the best-seller in time, which never goes out of print."