. . . [H]is soul was mad. Being alone in the wilderness, it had looked within itself, and, by heavens! I tell you, it had gone mad.

It is Marlow’s compelling argument, and through Marlow, Conrad’s, that the mind of man is capable of anything ‘‘because everything is in it, all the past as well as all the future.’’ Marlow’s (and Conrad’s) journey up the Congo is, in one sense, a journey back into time: beginning with Marlow’s apprehension that England, too, was once ‘‘one of the dark places of the earth’’ and moving to a consideration of the ‘‘fascination of the abomination’’—the fascination of civilized man for his primitive, atavistic roots. What romance there is in Conrad’s prose, in his celebration of such truths: ‘‘The voice of the surf heard now and then was a positive pleasure, like the speech of a brother.’’ And in the memorable passage in which Marlow describes his excitement at setting out, at last, to meet the mysterious chief of the inner station, Kurtz:

Going up that river was like travelling back to the earliest beginnings of the world, when vegetation rioted on the earth and the big trees were kings. An empty stream, a great silence, an impenetrable forest. The air was warm, thick, heavy, sluggish. There was no joy in the brilliance of sunshine. . . . [Y]ou lost your way on that river as you would in a desert . . . till you thought yourself bewitched and cut off for ever from everything you had known once—somewhere—far away—in another existence perhaps.

The anxieties aroused by Charles Darwin’s controversial, bitterly contested theory of evolution by way of natural selection, first promulgated in Origin of Species (1859) and subsequently in The Descent of Man (1871) are given tragic dramatic form in the tale of Kurtz’s deterioration in the jungle, the much-acclaimed Kurtz of whom it is said by Marlow that ‘‘all of Europe had gone into [his] making.’’ Conrad’s irony is a constant throughout the narrative, like a haunting vibration beyond the sounds of words normally uttered. And what intransigent irony in Kurtz’s final words, as if Shakespeare’s unregenerate Edmund, or Iago, and not Lear or Othello, were the touchstones of moral truth. Dying of fever in the jungle, as Marlow nearly dies, Kurtz’s famous pronouncement of his own spiritual condition— ‘‘The horror! The horror!’’—is a judgment upon man’s universal propensity for evil. What is this mysterious kinship that Marlow feels with the doomed man, whom he has traveled hundreds of miles to meet, only to discover him moribund, hideous? ‘‘It was as if an animated image of death carved out of old ivory had been shaking its hand with menaces at a motionless crowd of men made of dark and glittering bronze.’’ (Compare Marlow’s subterranean connection with Kurtz to the idealized and romanticized connection between the immature young captain of ‘‘The Secret Sharer’’ and his double, the fugitive Leggatt.) Yet, in his symbolic role as chief of the coveted inner station, Kurtz is indeed, as Marlow claims, a remarkable man:

[H]is stare . . . was wide enough to embrace the whole universe, piercing enough to penetrate all the hearts that beat in the darkness. He had summed up—he had judged. ‘‘The horror!’’ . . . It was an affirmation, a moral victory paid for by innumerable defeats, by abominable terrors, by abominable satisfactions. But it was a victory! That is why I have remained loyal to Kurtz to the last. . .

(Kurtz’s real-life model was a man named Georges Antoine Klein, an employee of the Brussels-based trading company Société Anonyme Belge pour le Commerce du Haut-Congo, whom Conrad met shortly before Klein’s death.