In the fall of 1849, Gustave Flaubert invited his two closest friends—Louis Bouilhet and Maxime du Camp—to hear a reading of what he believed was to be his masterpiece: a retelling of the temptation of St. Anthony. The 30 year-old writer had been working on it for four years, and he was excited to finally share it with the two men whose opinion he trusted more than anyone else. Bouilhet and du Camp were likewise excited; they both knew of his extraordinary potential, and were anxious to hear this masterwork that had so fully consumed him. He read the entire five hundred and forty-one pages straight through: eight hours a day in uninterrupted four-hour blocks of time, for four solid days. Bouilhet and du Camp would later remember it as the most painful days in their lives, as they listened to an endless morass of words that was alternately incomprehensible, banal, repetitive and childish. After it was over, they did their best to put a good face on it, and to let him down easy; Bouilhet, with as much tact as he could muster, told Flaubert simply, “We think you should throw it into the fire and never speak of it again.”

Instead of continuing to work on the Temptation, they challenged him instead to write something completely devoid of romanticism and symbolism—something instead minutely detailed, objectively reported, as in the vein of Balzac. And so Flaubert wrote Madame Bovary, the book that changed not only his life but changed forever contemporary literature—and which, one could say, was the result of something crossed between a dare and a punishment.

And still, Flaubert never gave up on the Temptation. He rewrote it three times over the course of his life, spending close to three decades trying to get it right, finally publishing it in 1874. Even as he was writing Sentimental Education, Salammbô, and Bouvard and Pécuchet, he never forgot it, and yet it cannot begin to compare to those other works. The Temptation was the ghost lingering behind all of Flaubert’s better works; in the words of Michel Foucault, “The Temptation seems to represent Flaubert’s unattainable dream: what he wanted his works to be — supple, silky, delicate, spontaneous, harmoniously revealed through rapturous phrases — but also what they must never be if they were to see the light of day.” It became the thing he returned to time and time again, always the antithesis of his great writing, and it stood in stark opposition to the works by which he is now mostly known. “Suspended over his entire work,” Foucault writes, “it is unlike all his other books by virtue of its prolixity, its wasted abundance, and its overcrowded bestiary; and set back from his other books, it offers, a photographic negative of their writing, the somber and murmuring prose which they were compelled to repress, to silence gradually, in order to achieve their own clarity. The entire work of Flaubert is dedicated to the conflagration of this primary discourse: its precious ashes, its black, unmalleable coal.”

The first English translation was by Lafcadio Hearn, begun in 1875, and it remains perhaps the best translation available. As Marshall C. Olds notes in the recent Modern Library edition, Hearn’s rendering—somewhat archaic, anachronistic, and baroque—best matches the strange, baroque quality of the original. The Temptation is one of those few works that does not benefit from a modern translation; the further it recedes into the past, the more compelling the book feels.

That said, even in this form the work is difficult to read. It remains, stubbornly, as du Camp and Bouilhet largely first heard it: repetitive, without much direction, and strangely empty of feeling despite its wild imaginings and endless litany of strange figures. Written not as a novel, but as an impossible play, the creatures summoned to taunt Anthony are described in bare-bones stage direction, and so even as Anthony himself cowers or stands in awe, we have little of the same feeling towards these strange monstrosities:

Then idols of all nations and of all epochs—of wood, of metal, of granite, of feathers, of skins sewn together—pass before them. . . . The more that the idols commence to resemble the human forms, the more they irritate Anthony. He strikes them with his fists, kicks them, attacks them with fury. They become frightful—with loft plumes, eyes like balls, fingers terminated by claws, the jaws of sharks.

If the speeches rehearsed by these monsters are meant to inspire wonder or horror, they often fail by virtue of their bloodless depiction: “Respect me! I am the contemporary of beginnings,” cries Oannes, a creature whose body is half fish, half man. “I dwelt in that formless world where hermaphroditic creatures slumbered, under the weight of an opaque atmosphere, in the deeps of dark waters—when fingers, fins, and wings were blended, and eyes without heads were floating like mollusks, among human-faced bulls, and dog-footed serpents.”

But perhaps the real draw of the Temptation is not its readability; its strengths lie elsewhere. Oannes is just one of many creatures in Flaubert’s book that may at first glance to seem to be a product of his imagination, but which was not. An ancient Mesopotamian god who supposedly taught early man writing, art and science, Flaubert learned of him through the writings of the third century BCE Babylonian writer Berossus. As it happens, nearly all of the creatures in the Temptation are figures that Flaubert found in archaic chronicles and encyclopedias: the book is less one of imaginative fancy than it is meticulous research and compilation. What’s remarkable about the Temptation is how it records, with minute accuracy, Flaubert’s research; while it may seem the result of a fevered hallucination, something akin to “Kublai Khan” or the paintings of Bosch, it’s instead a record of copious bibliographic study—and it is this which is perhaps most noteworthy about its composition. “The fantastic is no longer a property of the heart,” Foucault writes, “nor is it found among the incongruities of nature; it evolves from the accuracy of the knowledge, and its treasures lie dormant in documents. Dreams are no longer summoned with closed eyes, but in reading; and a true image is now a product of learning.” The result of prodigious reading, and yet nearly unreadable itself, it would be almost a decade before the Temptation came alive.

“Here is the nightmare transported into art,” J. K. Huysmans wrote of Odilon Redon’s work in 1881. “Plunged into a macabre milieu, imagine somnambulistic figures, twisted with fear, having a vague kinship with those of Gustave Moreau, and perhaps you will have an idea of the bizarre talent of this singular artist.” Redon (1840-1916) had been working in lithography since around 1870, developing a singular style that anticipated both the decadent symbolism of the late nineteenth century and the modernism of the early twentieth. Redon’s milieu borrowed largely from the gothic folktales of his childhood, to which he borrowed a pictorial vocabulary from an unlikely place: the grotesque cartoons of political satire, with its half-politician half-animal hybrids, its exaggerated facial features and deformities, and the tone of decadent depravity. This Redon adapted to his darker subject matters, creating, in his Origins series and his noirs, which depict a nightmare landscape where spiders have human eyes and flowers have faces. (J. K. Huysmans, meanwhile, would later pay another form of homage to Redon; in his classic À Rebours, his protagonist des Esseintes collects prints by Redon—a move that helped catapult Redon’s work into the mainstream.)

Redon had been working for over a decade when the third and final version of Flaubert’s Temptation was finally published; “It is a literary marvel and a mine for me,” he wrote of the book, in which he saw an endless litany of bizarre figures and distorted creatures that he could adapt as inspiration. Their work formed a natural kinship; as Stephen F. Eisenman comments, “Like Flaubert, Redon saw himself as unique, an accident, a monster, and all the more remarkable an artist for these very reasons.” Redon began producing a series of plates based on the Temptation, work which finally unlocked the strangeness and decadent symbolism that Flaubert had dreamt of but which he could never quite evoke on the page.

In perhaps the most striking and well-known example, Redon took Flaubert’s image of death, rendered by the author in a bare bones description (“It is a death’s head with a crown of roses. It rises above a woman’s torso, pearly white. Beneath this, a shroud with dots of gold acts as a sort of tail—the whole body undulates, as might a gigantic worm lifting upright.”), and renders a figure of terrible beauty. All of Flaubert’s components are there, from the roses above to the “sort of tail” below, but Redon’s composition has turned them into something else entirely: the skull is half-obscured in darkness, turned away in either longing or disgust, while her body emerges out of pure blackness. The sense of both endlessness and motion conveyed by the tail spiraling out below her, and the garland of roses streaming out from her head, goes well beyond Flaubert’s original writing—Stephen Mallarmé would later write to Redon, “I am stupefied by your Death. . . I do not believe any artist has ever made, or poet dreamed, an image so absolute!”

Other images are far stranger, following Flaubert down the rabbit hole of a world where bodies and shapes are free of any seemingly natural order. Redon’s mastery at using light and shadow, particularly in his use of the pure black that lithography offered, properly evoked the sense of mystery and despair that Flaubert had intended but could never quite create. Redon’s bestiary offers a richer manifestation than Flaubert’s blueprint, particularly his sphinx and chimera, or the half-ostrich, half-ape figure that accompanies Flaubert’s line “There must be, somewhere, primordial figures whose bodies are nothing but their images.” And then there is Oannes, rendered by Redon as a pensive face mounted on a body that swirls up from the darkness.

But while these figures may have seemed strange, beyond the ken of nature, Redon was as inspired by the recent work of Darwin and Cuvier as he was of by medieval bestiaries. Increasingly vigorous taxonomists and scientific explorers were reporting back an increasingly bizarre litany of animals far stranger than those dreamed up by the human imagination. “Science recognizes no monsters,” says Jules in Sentimental Education; which is to say, that in science an artist could find ample inspiration for the monstrous. Just as Flaubert’s work represents a mind rigorously compiling monstrosities of the library, Redon’s work reflects a mind gleefully intermixing images from religion and science, allowing monsters whose bodies are nothing but their images. As Eisenman writes, his images for the Temptation read like “anagrams,” inviting “the viewer to create order out of the apparent chaos.”

Redon’s work, which caused a sensation in its day but has too often been neglected (particularly outside France), represents perhaps the true potential, and use, of Flaubert’s Temptation. An alchemy of Flaubert’s research, his excessive documentation of strange beasts and foreign gods, brought to life by a pictorial imagination that could make use of everything from political satire to naturalists’ field reports, is what finally brings Anthony’s struggle to life, and finally makes clear the horror and awe in his eyes as Redon’s bestiary parades before our eyes. Flaubert’s Temptation is less a book to be read then it is an archive that can be endlessly plundered. As Redon’s work amply demonstrates, there is material left there to mine.