Heralded by Albert Camus and Thomas Mann and widely translated, "The Tunnel" is the brief, obsessive, sometimes delirious confession of a convicted murderer. Although Sábato has been a passionate and voluble essayist throughout the intervening decades, he has been less prolific as a novelist. "On Heroes and Tombs," first published—to worldwide acclaim—20 years ago (we in the English-speaking world are the last to get the news), is his second novel, and there is only one other, "Abaddon, the Exterminator," which came out in 1974 and later won the prestigious French "Prix du Meilleur Livre Etranger."

Yet, for all his reputation, Sábato stands apart from most of the writers of the "Boom"—and for good reason. Not only does he not participate in their communal voice, he is at war with it. He calls such writing "gratuitous" fiction, effete and superficial, a sophisticated ivory-tower pastime. He has...